2020 NEC FAQ's

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Dennis Alwon

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  • Am I required to install a Concrete-Encased Electrode if one isn't already present?
No. 250.50 requires the installer to make use of all electrodes present. If there is no CEE to begin with, then there's none to bond.

If there is not one present, you are free to add one if you'd like, two methods are offered in 250.52(A)(3).

The change in the 2005 text was to make it more evident to installers that covering a CEE in concrete does not alleviate our need to connect to it for our grounding electrode system. The CEE (or "Ufer" as it's commonly called) is a very effective grounding electrode for an almost negligible additional cost in most cases, and proposals were submitted to force everyone into noticing. The 2020 as well as other earlier versions of the nec now requires all electrodes available to be used. This means that in new construction a concrete encased electrode must be part of the grounding electrode system. The only exception is for existing buildings. The nec does not require you to chop up the footing to get to an electrode in an existing structure.

Be sure to check local codes before concrete is poured. There has been cases where the inspector made the electrician chop thru the footing to connect to the concrete encased electrode. In NC there is an amendment to forego the requirement to connect to a concrete encased electrode.

Related links:

Grounding Electrode System - Concrete encased electrode as a sole electrode
 
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Dennis Alwon

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  • Is a green ground screw required in metal boxes?
No. There is a requirement for the main bonding jumper screw of a service to be green: 250.28(C). There is also a requirement for the grounding terminal for a device to be green, 250.126.

250.8 forbids the use of sheet metal screws for connecting EGCs to enclosures.

250.148 (C) requires the screw used to bond a metal box not to be used for another purpose.

Related Threads:
Grounding Screw? - Mar 2005. Started by Jason32, with 23 replies.
 

Dennis Alwon

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Metal Water Pipes in Detail
  • Is a metal water pipe a primary grounding electrode, and others secondary?
An electrode is an electrode. Some perform better than others, but the NEC takes a basic stance that all present shall be used, and the order does not matter.

250.64(F) says that a GEC can run to any convenient electrode, and then "daisy-chain" from electrode to electrode if we like. The GEC for some electrodes is not required to be larger than a certain size, like #6 for a ground rod. If you were to pull a GEC to the ground rod first, then run a bonding jumper from the ground rod to a water pipe, then you would be forced to pull a larger-than-6 conductor to the ground rod due to the sequence of electrodes pulled to.

The water pipe needs a full sized GEC all the way back to the service. Therefore, it's a little counterintuitive to run to a ground rod first.

We can also pull GECs to each grounding electrode if we prefer.
  • Are we required to install ground rods when a metal water pipe is present?
Not exactly. A metal water pipe grounding electrode is required to be supplemented by another electrode (250.53(D)(2)). If there is a concrete-encased electrode and a water pipe in the same structure, then no additional grounding electrodes are necessary.

If a metal water pipe grounding electrode is the sole electrode at the structure, then it must be supplemented somehow, and the easiest is a ground rod.
  • Are two ground rods required to augment a metal water pipe?
If a ground rod is driven to augment a water pipe, and the single ground rod's resistance to ground is greater than 25 ohms, then a second is to be driven, according to 250.53(D)(2).

If you can't afford expensive testing equipment, you can drive a second rod and walk away regardless of the resistance of the system.

The NEC does not have any requirement for the overall resistance of a system. It only has a rule that states that a single ground rod must be augmented if it's resistance is over 25 ohms. Proposals to eliminate this requirement, or to increase the requirement have both been rejected.​
  • What if the water pipe is replaced for plastic later?
That's why we supplemented it with ground rods (or other electrodes) - by the nature of it's use, it's vulnerable to changes later in it's life, unlike the other electrodes.
  • If the water pipe entering the building is plastic, and the water pipes inside the building are metallic, do the metallic water lines require grounding?
No, but they do require bonding. See 250.104(A).

The bonding conductor does not have to be to any specific area of the water piping (as opposed to the metal water pipe grounding electrode described in 250.52(A)(1), which has to be connected to within 5' of the entrance to the building).
  • Does this mean that all metal water piping in a structure has to be bonded, per 250.104?
All metal water piping systems are required to be bonded. Therefore, plastic piping with metallic fittings do not require bonding per the NEC.
  • Does this mean that I have to bond around a water heater - isn't there a hot system and a cold system?
This is not clear in the NEC. One thing that is indisputable (in my opinion) is that if there are metallic mixing valves at the sinks and/or tubs, then the piping is electrically continuous.

Click here to see a discussion on the topic, which was never resolved, IMO. It may help you to form your own opinion. Essentially, the debate was what constituted a "system", and what may go legally unbonded by the NEC. According to a panel statement that Mike Whitt (jwelectric) found, the hot water pipes would need to be bonded only if likely to become energized, by 250.104(B).
 

Dennis Alwon

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  • What codes apply when replacing old non-grounding receptacles in an existing structure?
Device replacement of the receptacles themselves are covered in 406.3(D). Some more flexible rules for installing an EGC in an existing structure are given in 250.130(C).

Please note that the goal when using one of these alternate methods is to ensure that an effective ground-fault-current path is provided. Care should be taken to be absolutely sure that the electrode connected to is in fact connected to the neutral of the service of the building served. The earth is of no consequence to a receptacle, a normally non-current-carrying solid connection back to the electrical source is what we desire.




Related threads:
Grounding of Rec.
 

Dennis Alwon

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  • Am I required to run an equipment grounding conductor in a feeder to a detached structure?
Yes, as of 2008 NEC we are required to run an equipment grounding conductor with the feeder to a detached structure.
 

Dennis Alwon

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  • Am I required to upsize the Equipment Grounding Conductor when upsizing for voltage drop?
Yes, see 250.122(B).

In fact, it does not matter why the conductors have been upsized (as in, voltage drop). If you decide to use 10 AWG ungrounded conductors on a 20A circuit from sheer eccentricity alone, you are still required to upsize the EGC proportionately.

Given that Table 250.122 requires the same size EGC as the ungrounded conductors, then we are faced with having to directly upsize the EGC to the same size as the ungrounded conductors the whole way, because the proportion is 1:1.

With larger circuits it is not so extreme. Example:

A 50A circuit is wired with CU THHN in EMT. The required conductor size is #6. The installer chooses to upsize the conductors three times to #1, due to distance and voltage drop.

#1 is 83680 circular mils.
#6 is 26240 circular mils.
Difference is 57440 circular mils, or a factor of 3.1894 (83680 / 26240) proportionately.

Prior to upsizing the circuit for voltage drop, 50A circuit normally requires a #10 CU conductor (Table 250.122). A #10 has 10380 circular mils (Table 8).

10380 x 3.1894 = 33106 circular mils. The installer must use a #4 EGC (41740 cm) for this circuit.
A primary reason for this requirement is that when you upsize the ungrounded conductors, you increase the available fault current at the same time. The short and sweet explanation for this is, fault current is determined by the size of the conductors supplying the fault, along with other factors.

To go for a plumbing analogy, imagine one day you decided to upgrade the 3/4" main water pipe coming into your house with a 4" main, from the street. To carry this a bit further, let's say you upsized the piping all the way to your master bathtub. You are into extreme showers. :D

You've upgraded all the supplying pipes, but didn't bother with the drains because they're not as interesting. It's hard to envision an extreme shower drain. You'll never see one in a Mountain Dew commercial.

What happens? The bathtub can't drain as fast as it takes water in, so the tub fills.

Moving back to conductors and electricity, Table 250.122 is based on normal conductor sizes. If you increase the ungrounded conductor size, leave the EGC at the normal small size, then you increase the likelyhood of burning up the EGC in the event of a ground fault.
People that first hear of the rule often remark, "That's stupid! Why would a #10 not work for a 20A branch circuit using #6 wire, when it will be just fine on a 20A breaker?" Here's a quote from Don:
don_resqcapt19 said:
There is no technical rationale for this issue. It is just a result of the oversized equipment grounding conductors that are required by 250.122 for 15, 20 and 30 amp circuits. To write a rule to cover these wire sizes would complicate this issue even more that it is now.

Related Links:
Voltage Drop and the EGC - Oct 2006. Started by me, includes the explanation from Don above. 30 replies.
 

Dennis Alwon

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  • How do I calculate voltage drop?
There are several calculations available.

The formula I use most frequently is:

VD = 2 x R x I x D (single phase)
(2 x Resistance x Amps x Distance)
VD = 1.73 x R x I x D (three phase)
(Square root of three x Resistance x Amps x Distance)


It's easy to remember, to rid yourself of voltage drop.

The 2 in the single-phase equation above is due to the number of conductors of the circuit: there is a hot and a neutral, two conductors. If the load is three phase, the current travels along all three wires, so it is more efficient.

Example: You want to know what the voltage drop is for a single phase 120V 16A load on a 20A branch circuit wired with THHN, 300 feet from the load.

Look at Table 8:
Remember, the number is the resistance for solid wire, 1000' long, so this number must be divided by 1000' to get the resistance per foot.

Plug this into the formula:

Vd = 2 x R x I x D
Vd = 2 x .00193 x 16 x 300
Vd = 18.5V dropped
120V - 18.5V = 101.5 V at the load
120V / 101.5V = 84.58% available, or
1 - .8458 = .1541 = 15.41% voltage drop.

Too lazy for math? Try this Online Voltage Drop Calculator.

Related Threads:
Voltage Drop Calculation Question - Feb 2008. Started by FloridaSun, 7+ Replies. How do you calculate voltage drop on light poles, since the load is less as the circuit reaches it's end?
 

Dennis Alwon

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  • When is voltage drop required to be considered in the NEC?
In 695.7, you are required to consider voltage drop when dealing with fire pumps.

In 647.4(D), you are required to consider voltage drop when dealing with sensitive electronic equipment.

That's it.


99% of installations performed under the NEC do not have any mandatory rule concerning voltage drop. There are Fine Print Notes in 210.19(A)(1), 215.2(A), and elsewhere in the NEC. However, FPN's are not enforceable rules, they are informational only. See 90.5(C).
 

Dennis Alwon

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Standard Load Calculation

Standard Load Calculation

  • What are the steps to a basic standard load calculation?
Step 1: Demanded General Lighting Load - (including SABCs and Laundry if applicable)

  • Determine the type of structure, and look at Table 220.12 to determine the general lighting load by occupancy.
For example, a church requires 1VA/square foot for lighting.

A dwelling unit requires 3 VA/square foot for lighting - but notice the reference to footnote a of the table. Receptacle outlets are included in this 3VA/square foot number. Also, notice that 220.52(A) and (B) allow the SABCs and the Laundry circuits to be included in the general lighting load (prior to demanding the load).

Looking at Annex D (on page 717 of the 2005 NEC), the first example is a one family dwelling. The general lighting load is added to the SABCs and the Laundry, and then "demanded" down to a lower number. What this means is that the actual demand load will be lower, because it is highly unlikely that all the lights, SABCs and Laundry circuits will be in use and used to their capacity at the same time. The writers of the NEC realize this, and allow us to reduce the service size somewhat on account of that fact.

A bank requires 3.5 VA/square foot - but notice the reference to footnote b of the table? Be sure to keep an eye on details such as this, it makes a difference in the calculation. Some test questions are geared towards testing the individual's attention to details such as these notes. Depending on the situation, the real number could be 4.5VA/square foot for a bank.

Step 2: Fixed Appliances - In a dwelling unit, four or more appliances may be demanded down to 75% of their nameplate rating (220.53).

Step 3: Range - Ranges may be calculated in accordance with Table 220.55.

Step 4: Dryer - The minimum load for a dryer in a calculation is 5kW (220.54). They can be demanded down according to Table 220.54.

Step 5: Heating - A/C - Calculated at 100% of the larger load. (220.51, 220.60)

Step 6: 25% of largest motor load - Add 25% of the largest motor load per 220.18(A).
 

Dennis Alwon

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  • How do I calculate box fill?
The requirements for box fill are given in 314.16(B). The easiest way I've found is just to take it step by step:

(1) Conductor Fill. (Each conductor counted once, unless it's a long unbroken one (twice)).
(2) Clamp Fill. (On the inside of box counted once, outside not counted, based on largest conductor in box).
(3) Support Fittings Fill. (In the box counted once, based on largest conductor in box).
(4) Device or Equipment Fill. (Each device counted twice, based on conductor connected to device).
(5) Equipment Grounding Conductor Fill. (The biggest EGC is counted once.)

The total number of conductors are then multiplied by the cubic inches used, as given in Table 314.16(B).
 

Dennis Alwon

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  • Do you install three-ways and fourways so the load is off when the switches are all down?
It is entirely a preference decision, just like whether grounds should be up or down. In the past, we have had customers who prefer that the 3 ways be wired so that in the down position the light is always off. This is easy to do. If you install the travelers the same at both switch then one threeway must be put in the box in the opposition position from the other.

If you change the travelers in one 3 way switch then the switches must be mounted to the box in the same manner
 

Dennis Alwon

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  • Should I join or avoid a Union shop?
This topic is prohibited by policy. This topic brings out very passionate (and many times hurtful) responses from both Pro- and Non- Union individuals. It is a friendship-killing topic that will be stopped in it's tracks as soon as it is reported to and/or seen by a moderator.

If you are curious about why you should join or avoid a union, feel free to Private Message individuals about the topic. Union members are not prohibited from mentioning their affiliation in their signatures, and many do. They can be located and contacted with minimal difficulty.

If you would like to be added to this list as an advocate for either merit or union employment, feel free to PM me. Being added to the list on this post means that you would be willing to recieve PM's from members wishing to discuss this issue privately.*

*All members should bear in mind that the same rules of conduct apply to private messages as well as public posts, but are not visible to moderators. Anyone who would use this list as a means to harass or otherwise offend those members who've chosen to be a part of this list, will be subject to immediate suspension of their membership from this forum.
 

Dennis Alwon

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The UL White Book

The UL White Book is a profoundly helpful publication by the Underwriters Laboratories that works hand-in-hand with the NEC (in most cases). Many times, there is a practice or use for a listed item that is not mentioned in the NEC, and can be cleared up by looking at how the item was listed.

The UL White Book can be searched online. The entire 2015-2016 UL White Book can be downloaded immediately in .pdf format by clicking on this link: download of White Book.

One easy way to search for the information you're looking for is to use "ctrl + F" for a PC and "Command Key + F" for a Mac and type in the product you are interested in.

For example, I'm mostly familiar with Cooper receptacles. If I want to know the listing requirements for receptacles in general, it's still helpful to add the name of a manufacturer I am familiar with, to get more closely related hits.

Bear in mind, the UL is not the only NRTL around, but they are the most easily recognized.

Related Links:
How to Use the UL Book
 
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Dennis Alwon

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Etiquette

Much of what is posted here is taken from this source. I have taken the liberty of bolding my personal favorites.

Certain rules of unspoken etiquette are recommended to be followed when using Internet forums. They include:
  • One should read all the rules and guidelines established by the community; some communities may have different regulations on a particular subject.
  • One should always be courteous.
  • Before creating a new topic thread, one is advised to search to see if a similar topic already exists.
  • Contributors should follow standard grammar and spelling rules and avoid slang.
  • If the forum is categorized, one should strive to post in the correct section.
  • When making a technical inquiry, one should include as much technical information as possible, especially in the subject line.
  • Contributors are asked to stay on-topic.
  • Contributors should avoid double posting and Crossposting.
  • To avoid appearing self-absorbed, one should respond to topics started by others more often than starting topics of their own.
  • Contributors should avoid the use of all CAPITAL LETTERS in posts. All CAPS is considered "shouting" and causes readability issues.
  • One is advised not to resurrect a very old topic if nothing significant will be added. This practice is known as revival or Necroing.
  • One should try to refrain from lashing back at a poorly behaving member or participating in a flame war; instead, notify the messageboard's staff of the event.
  • When quoting a previous post, one should only include the relevant portion of that post. Contributors are requested to keep in mind that their audience can likely still see the message they are quoting on the same screen and can read it again if need be. Click here to see detailed instructions on how to do this effectively.
  • Try not to edit a post after other members have already replied to your original. If you forgot to mention an important detail in your original post, simply post another reply in the thread with the follow-up information. It can be very confusing for other members who are unaware of the edit.
  • Try to avoid cursing. This site consists of probably 50% construction workers, who are reknowned for their ability to curse. Cursing does not add to a post, and the non-construction workers probably find it offensive. One aspect of this site that makes it special is that people from all walks contribute here, and cursing can turn people off from the site, whose contributions we value greatly. We don't need professionals getting turned off and leaving due to rampant cussing. A guideline I use is when I would normally say "p***ed", I simply switch it to "ticked", it works just as well.
  • Avoid bathroom humor and sexual innuendo. It will be deleted. People come here for help with technical issues, to advance their knowledge of products and theory, and to talk shop. This site is restricted to electrical professionals only, which makes this site somewhat unique, so try to act professional. Humor definutely adds to the mix here, it's half the reason to be here: but it does not need to be dirty to be funny.
  • Try to split your posts into paragraphs. They're easier to read. Admittedly, some of us type a sentence a paragraph, which is a touch excessive - but it beats giving headaches to the reader by packing a lot of information into a solid block of text. It also encourages people quoting your post to take the single small paragraph they are really focused on.
 

Dennis Alwon

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Etiquette II / Quoting Primer

Etiquette II / Quoting Primer

Sometimes, when posting a response to a particular post, you really are replying to the post in it's entirety. In that case, it's more appropriate to simply set your reply up as you would type a letter, and simply say the person's name at the beginning of the reply:

Fred, I disagree with your post. Grass is definutely green.
instead of

fred said:
Grass can be blue, orange or any other color. Look at these pictures of grass I have doctored with photoshop:
(picture)
(picture)
(picture)
Obviously, some doctoring was necessary in order to convey the point I am trying to get across, which is that I'm unwilling to admit that I'm wrong and crow is poisonous to me. In general, George is just typing to make this fake post seem longer and more complicated, which is difficult considering the generic topic he has chosen. In fact, he probably would have been better served to have selected a couple of real examples of each method of posting, and saved himself some trouble. But, after all, why stop while you're having fun, right? And besides, it would look like I was singling somebody out for doing this, right? Grass can definutely be purple.

Deal with it.
I disagree, grass is definutely green.
This is especially helpful when the quoted post has several large pictures in it. There is very little point in reposting the pictures in the quote. If a particular picture is important to your reply, then simply say "the third picture" for example, it's much kinder to the reader.

Are you not sure how to single out a single sentence of a post to quote? Here's a primer. Let's look at the quote above, the long one. I want to expose Fred for the photo-doctoring yutz he is.

I hit the "quote" button in Fred's post, and see the following in the message window:


It's really the first sentence that proves Fred is a photoshopping SOB. So, click and drag, highlighting everything from the end of the post backward:




Now, you hit delete. But, computers being computers, something broke:




The [/quote] tag on the end accidentally got half-deleted, because Windows machines like being overly helpful and highlighting words instead of letters the way they should. Your computer is deciding for you that the [/ at the end of what you deleted is part of the last word you actually wanted deleted. So, you have to type it back into the end of the quoted post for it to look right.

Then just type in your reply.



The finished post looks like this:


The extra effort makes your posts easier to read. Sometimes, it's hard to understand where 'what's quoted' ends, and where the reply begins. Feel free to PM me if this doesn't help and you'd like more help figuring this out, many folks already have and are happier with their experience here.

If you want to practice, feel free to put practice posts up on this thread.

If you want to learn how to do a quote within a quote, or multiple quotes from different people in the same reply, click here.
 

Dennis Alwon

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Grounding Vs. Bonding
The Big Picture

  • What is ?grounding?? What is ?bonding?? What?s the difference?
Grounding and bonding is probably the most discussed issue here, aside from 210.52?s design requirements.

The terms are defined in Article 100 and 250.2 of the NEC. Section 250.4 provides the performance requirements of Article 250. Grounding is a connection to earth, and bonding is the connection of items to each other.

Bonding is crucial inside a structure, because without it, if something goes wrong and an ungrounded conductor comes in contact with a piece of metal that someone can touch, that someone will receive a shock and potentially be electrocuted due to the uncleared fault. A quick and dirty definition for bonding is connecting electrical devices together in the attempt to trip a breaker, if an ungrounded conductor touches surface metal associated with the system.

What does the earth have to do with this? Nothing.

Then why is it called an ?Equipment Grounding Conductor (EGC)? in the NEC if it?s primary purpose is to ?bond? things together?
Simple answer: tradition. It?s always been called that, and the terms in the NEC have served to confuse people for a long time. Proposals have been made to change the term, and progress has been made, but the EGC continues to hold it?s misnomer.

Electricity does not seek the path of least resistance to the earth. It seeks all available paths back to it?s source, in proportion to their resistance. The reason that a person gets shocked when touching an ungrounded conductor and the earth is because the neutral of the system is repeatedly connected to earth in a grounded electrical system. The earth becomes part of a return path to the transformer ? it?s part of one route back to the source; the earth is not the destination for the electricity.

Driving a ground rod to ?ground? any electrical equipment does not provide the low-resistance path required to trip breakers. Driving a ground rod, or using a Ufer, or a metal water pipe is not a substitute for an EGC. A ground rod with 25 ohms to earth will allow almost five amps to escape the system into the earth when directly energized from a 120V source. Five amps will never trip a 15A or 20A breaker, and in the meantime everything bonded to this ground rod will be energized to 120V.


Bob Ludecke has created a powerpoint presentation under the 2002 cycle, and has granted permission for a link to be posted for download. Chris Knight has graciously provided a site for downloading the presentation:
http://www.tirebiter.net/downloads/ludecke.html

Thanks to both Chris and Bob for their help on this very important topic! :)

http://www.mikeholt.com/graphics/touch.gif
http://www.mikeholt.com/graphics/touch2.gif

If any of the items discussed here does not make sense to you, or if you disagree, please start a thread publicly or send a private message to me to discuss it privately, if you desire. It is critical that this issue be understood to ensure the safety of everyone involved.
 

Dennis Alwon

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  • Is the neutral a current carrying conductor? How do I apply 310.15(B)(4)?
First the silly answer: the neutral always carries current.

310.15(B)(4) tells us that we don't need to account for neutral conductors that only carry 'the unbalanced current from other conductors of the same circuit'. These conductors still carry some current, but we are permitted to ignore them in our accounting when applying the adjustment factors of table 310.15(B)(2)(a).

This is found in two common situations.

1) A single phase feeder or multi-wire branch circuit consisting of two 'hots' (ungrounded conductors) and a single 'neutral' (grounded conductor). In this case, the neutral carries only the unbalanced current of the two hot conductors, we would count a total of two current carrying conductors.

2) A three phase feeder or multi-wire branch circuit consisting of three 'hots' (ungrounded conductors) and a single 'neutral' (grounded conductor) where the major portion of the load is linear. In this case, the neutral carries only the unbalanced current of the three hot conductors, we would count a total of three current carrying conductors.

The rest of the time we have to count the neutral.

To understand this, remember that 310.15(B)(4) is all about accounting, not about reality. This is about figuring out the correct number from 310.15(B)(2)(a) to apply, not about the minute details of how many conductors actually have a bit of current flowing on them.

The main requirement is that the conductor carry only the unbalanced current of the other conductors in the same circuit. This tells us that there have to be other conductors, and that these other conductors have to be able to carry the _balanced_ current of the circuit. If the other conductors can possibly carry all of the balanced current, then only the unbalanced current is left for the neutral. This is the case when 310.15(B)(4) kicks in. The neutral may carry some current, but it doesn't count for 310.15(B)(2)(a).

But if the 'hot' conductors are not balanced, then some of the balanced current must flow on the neutral. This this case with any single 'line-neutral' circuit, and is also the case when you have two phases of a three phase wye system sharing a neutral. The neutral carries both unbalanced and balanced current, and must be counted for 310.15(B)(2)(a).

Harmonics confuse this a bit: the neutral has to carry the _balanced_ triplen harmonic current of the load. We are permitted some leeway, but when the major portion of the load is non-linear, the neutral is no longer considered to carry _only_ unbalanced current from the other conductors, and thus must be counted.

-Jon

Related Threads:
Neutral as a current carrying conductor-- Started by Cnl4-- Feb 2007
Current Carrying?-- Started by tdecontrols, Feb, 2020

Edit to remove opening conversational remark, edit format
Edit to add related thread
 
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Dennis Alwon

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Noteworthy Links




EC&M: Tables, Examples, and Appendices - Chapter 9, Appendix B - Article written for EC&M by Fredric P. Hartwell (12/1995). (Link Ctsy of Celtic)



EC&M: The Middle Of The Wire Isn't It's End - Article written for EC&M by Fredric P. Hartwell (03/1998). Details the use of the 60 and 75 degree columns when determining ampacity. (Link Ctsy of Celtic)
Handicap Accessibility requirements for receptacles and switches
Charlie's Rule of Technical Reading - The NEC comes alive when read using Charlie's Rule. :)
NEMA Guide to Water-Damaged Equipment
The dangers of open neutrals - Article by Mike Holt.
Online Pulling Calculator
Short Circuit Calc and More-- Mike Holt
High Voltage Shock Presentation - Link csty of Larry Fine.
Receptacle Heights for ADA (Disability Requirements)
1901 NEC - Download location found by Bryan Holland.
Fluorescent Socket PDF - Describes the differences in sockets for different ballasts
ElectricianSmarts.com - link ctsy of emahler.
How to attach an Excel spreadsheet to a post
Drilling Glulams
 
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Dennis Alwon

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Location
Chapel Hill, NC
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Electrical Contractor
  • Am I required to bond the hot and cold supply pipes to the motor of a jetted tub?
*Note: There is some disagreement as to the interpretation of NEC-2005 680.74.

IMO, No. Check out 680.74:

680.74 Bonding. All metal piping systems and all grounded metal parts in contact with the circulating water shall be bonded together using a copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG solid.
Only the piping systems in contact with the circulating water are required to be bonded. Generally, these are plastic (supplied with the tub) so no bonding is required by the NEC.

This was an intentional lowering of the requirements in the 2005 cycle.


Panel Statement: The need for bonding in a bathroom differs from the need for bonding in a pool area. Electrical equipment of a hydromassage bathtub is not accessible to users of the tub. Only parts that can cause a voltage gradient in the bathtub need to be bonded. Section 680.74 has been concisely reworded to require the bonding of only the parts that present a risk of creating voltage gradients in the hydromassage bathtub. The panel's action on 17-183 supersedes the panel's action on ROP 17-153.
Related Threads:
Another jacuzzi tub bonding question?? - May 2007. Started by Jango,
Whirlpool Tub Bond Lug - May 2007. Started by gaelectric, 50 replies,
Hydomassage Tub Code Reference Please--Started by Vinniem
 

Dennis Alwon

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Location
Chapel Hill, NC
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Electrical Contractor
Quoting Guide II
Multiple Quotes
Quote within a Quote


If you would like to quote several posts in one reply, here's how to do it:

Stan says that GFCI's are not required in kitchens in post #2.

Fred says that receptacles in a kitchen are required to be no more than two feet apart in post #4.

1. Click on reply in Stan's post. The reply screen loads, with Stan's quote in quote bars, as described in the quoting guide. Erase the parts you don't wish to reply to, to save space and to clarify what you're responding to.

2. Type your reply to Stan's comment. Hit the enter key a couple times, when you're finished, to make a little space for the next quote.

3. Go to Fred's post and hit reply. The same result as #1 will appear and do the same as #2. You can do this for multiple people

4. Hit the preview post button, to make sure it went off as you intended.


Quote within a Quote
There are times when you want to quote someone who has already quoted another member. If you hit reply you will notice that just the current members post appears which makes things a bit more difficult. Here is what you must do.

1. Hit Reply-- you will notice that at the beginning of the quoted post you have [quote=members name] and at the very end you have [/quote]. This will quote everything inside these commands.

2. Highlight the quoted text in the post you originally hit reply to.

3. After the bracketed quote=members name type [quote] then paste the quoted post.

4. At the end of the post you pasted type [/quote]

This is what it will look like

[quote=Dennis][quote=my wife]I love you[/quote]
Oh honey I wish I felt the same[/quote]

This will display as below

Dennis said:
my wife said:
I love you
Oh honey I wish I felt the same
 
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