texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
Can a steel plate be used as a current carrying bus bar?
- Thread starter Jamesco
- Start date
- Status
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I don't see that that is being code. It would not be real hard to fix though.
@infinity
Found here?
250.92 (B)
Standard locknuts or bushings shall not be the only means for the bonding required by this section but shall be permitted to be installed to make a mechanical connection of the raceway(s)
And only needs to be bonded at one end, the service disconnect enclosure? Doesn't need to be bonded at the CT cabinet end the emt/connector nipples?
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That's because they are not listed for threading into what most people use them for, conduit fittings and Bell boxes.
UL Certifies (Lists) Conduit Fittings under the product category for Conduit Fittings (DWTT), located on page 141 of the 2015-16 UL White Book, pdf located atwww.ul.com/whitebook and also on UL Product Spec at www.ul.com/productspec and enter DWTT at the category code search field. In the guide information you will find that with or without a gasket/seal, all male threaded fittings and nipples have only been investigated for use with locknuts only and have not been evaluated for use with hubs.
Thankfully no inspector enforces this though.
What I do is flip the locknut above the plastic o-ring seal and use it to keep the seal intact.
Carultch
Senior Member
- Location
- Massachusetts
How does that keep the seal intact? Isn't the gasket meant to work with the shoulder of the fitting, rather than the locknut?
Update to this thread.
The Electrical Contractor finally sent someone out from his office to inspect the painted steel plate that the electrician was using as a conductor to connect the supply side grounded conductor to the load side grounded conductor.
Especially after I sent an email to my friends business email account telling him to forward it to the electrical contractor listing the two code violations I spoke of in this thread. Just a guess the part where I sent the picture of one of the code violations showing the painted steel plate with no evidence of the paint being removed where the two double barrel mechanical lugs were bolted to the plate.
I explained the only electrical continuity contact from one lug to the other lug was the side of bolts touching the side of the drilled holes in the plate. I said the poor connection could very well cause voltage swings, fluctuations, at the 120V receptacle outlets in his building. The voltage at the wall receptacles his computers and computers used for his production processing could have voltage swings from 120V to maybe 180V, or higher. I said no different that what would happen if the service neutral conductor connection was loose.
Funny how money talks.
Service was released, (by the city inspector that takes care of the area the business is located), for the POCO to connect power to the new service. Electrical contractor did not correct the 250.92 (B) supply side bonding code violation.
I contacted, by phone, two of the AHJ inspectors and got two different rulings on the reading of 250.92 (B). The first inspector said the regular locknuts did not meet the requirements of 250.92 (B). I said it appears the electrical contractor is reading 250.92 (B) wrong thinking the sentence on regular locknuts is directly tied to the sentence before where reducing washers, concentric and eccentric KOs are mentioned. I said the way I read the second sentence it is not conditioned on the preceding sentence. Even if all the concentric or eccentric KOs were removed the regular locknuts would not be an assured bonding means. He agreed.
He agreed with me the cheapest simplest way for the contractor to correct the violation now was to have his electrician install split grounding bushings on the 3" connectors and bond them to the grounded conductor in the main disconnect switch enclosure. (Sizing of bonding jumper 250.102 (A) (2)).
Call to second electrical inspector:
He said the second sentence, in 250.92 (B), was tied to the first sentence. If the KOs were punched out 3" for the 3" EMT connectors the regular locknuts are considered an assured bonding means.
Job has been final inspected, passed. Business owner has been billed for final payment and sent the full remaining payment to the contractor. I suggested I would correct the code violation, labor free, and only charge him for the cost of material. I suggested he then deduct the material cost from the final payment to the contractor. He said he just wanted to pay the guy off and be done with him. Fine with me! It's his money...
I ran across this YouTube Link were the person giving the vocal presentation does a good job of explaining 250.92 (A) and (B). Especially (B).
https://www.youtube.com/watch?v=Ucr6gJ_B5DY
You can skip the first part of his presentation and go directly to time marker 3:46 where he starts talking about 250.92 (A) & (B).
I did a web search to check his credentials.
https://www.electricalcodeacademy.net/founder
.
The Electrical Contractor finally sent someone out from his office to inspect the painted steel plate that the electrician was using as a conductor to connect the supply side grounded conductor to the load side grounded conductor.
Especially after I sent an email to my friends business email account telling him to forward it to the electrical contractor listing the two code violations I spoke of in this thread. Just a guess the part where I sent the picture of one of the code violations showing the painted steel plate with no evidence of the paint being removed where the two double barrel mechanical lugs were bolted to the plate.
I explained the only electrical continuity contact from one lug to the other lug was the side of bolts touching the side of the drilled holes in the plate. I said the poor connection could very well cause voltage swings, fluctuations, at the 120V receptacle outlets in his building. The voltage at the wall receptacles his computers and computers used for his production processing could have voltage swings from 120V to maybe 180V, or higher. I said no different that what would happen if the service neutral conductor connection was loose.
Funny how money talks.
Service was released, (by the city inspector that takes care of the area the business is located), for the POCO to connect power to the new service. Electrical contractor did not correct the 250.92 (B) supply side bonding code violation.
I contacted, by phone, two of the AHJ inspectors and got two different rulings on the reading of 250.92 (B). The first inspector said the regular locknuts did not meet the requirements of 250.92 (B). I said it appears the electrical contractor is reading 250.92 (B) wrong thinking the sentence on regular locknuts is directly tied to the sentence before where reducing washers, concentric and eccentric KOs are mentioned. I said the way I read the second sentence it is not conditioned on the preceding sentence. Even if all the concentric or eccentric KOs were removed the regular locknuts would not be an assured bonding means. He agreed.
He agreed with me the cheapest simplest way for the contractor to correct the violation now was to have his electrician install split grounding bushings on the 3" connectors and bond them to the grounded conductor in the main disconnect switch enclosure. (Sizing of bonding jumper 250.102 (A) (2)).
Call to second electrical inspector:
He said the second sentence, in 250.92 (B), was tied to the first sentence. If the KOs were punched out 3" for the 3" EMT connectors the regular locknuts are considered an assured bonding means.
Job has been final inspected, passed. Business owner has been billed for final payment and sent the full remaining payment to the contractor. I suggested I would correct the code violation, labor free, and only charge him for the cost of material. I suggested he then deduct the material cost from the final payment to the contractor. He said he just wanted to pay the guy off and be done with him. Fine with me! It's his money...
I ran across this YouTube Link were the person giving the vocal presentation does a good job of explaining 250.92 (A) and (B). Especially (B).
https://www.youtube.com/watch?v=Ucr6gJ_B5DY
You can skip the first part of his presentation and go directly to time marker 3:46 where he starts talking about 250.92 (A) & (B).
I did a web search to check his credentials.
https://www.electricalcodeacademy.net/founder
.
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
You don't say what was done with the neutral connected as shown in the photo. You keep mentioning that they didn't remove the paint. The paint is irrelevant as this is not a compliant connection in the first place. It wouldn't matter if they gold plated it-it needs a neutral kit.Update to this thread.
The Electrical Contractor finally sent someone out from his office to inspect the painted steel plate that the electrician was using as a conductor to connect the supply side grounded conductor to the load side grounded conductor.
Especially after I sent an email to my friends business email account telling him to forward it to the electrical contractor listing the two code violations I spoke of in this thread. Just a guess the part where I sent the picture of one of the code violations showing the painted steel plate with no evidence of the paint being removed where the two double barrel mechanical lugs were bolted to the plate.
I explained the only electrical continuity contact from one lug to the other lug was the side of bolts touching the side of the drilled holes in the plate. I said the poor connection could very well cause voltage swings, fluctuations, at the 120V receptacle outlets in his building. The voltage at the wall receptacles his computers and computers used for his production processing could have voltage swings from 120V to maybe 180V, or higher. I said no different that what would happen if the service neutral conductor connection was loose.
Funny how money talks.
Service was released, (by the city inspector that takes care of the area the business is located), for the POCO to connect power to the new service. Electrical contractor did not correct the 250.92 (B) supply side bonding code violation.
I contacted, by phone, two of the AHJ inspectors and got two different rulings on the reading of 250.92 (B). The first inspector said the regular locknuts did not meet the requirements of 250.92 (B). I said it appears the electrical contractor is reading 250.92 (B) wrong thinking the sentence on regular locknuts is directly tied to the sentence before where reducing washers, concentric and eccentric KOs are mentioned. I said the way I read the second sentence it is not conditioned on the preceding sentence. Even if all the concentric or eccentric KOs were removed the regular locknuts would not be an assured bonding means. He agreed.
He agreed with me the cheapest simplest way for the contractor to correct the violation now was to have his electrician install split grounding bushings on the 3" connectors and bond them to the grounded conductor in the main disconnect switch enclosure. (Sizing of bonding jumper 250.102 (A) (2)).
Call to second electrical inspector:
He said the second sentence, in 250.92 (B), was tied to the first sentence. If the KOs were punched out 3" for the 3" EMT connectors the regular locknuts are considered an assured bonding means.
Job has been final inspected, passed. Business owner has been billed for final payment and sent the full remaining payment to the contractor. I suggested I would correct the code violation, labor free, and only charge him for the cost of material. I suggested he then deduct the material cost from the final payment to the contractor. He said he just wanted to pay the guy off and be done with him. Fine with me! It's his money...
I ran across this YouTube Link were the person giving the vocal presentation does a good job of explaining 250.92 (A) and (B). Especially (B).
https://www.youtube.com/watch?v=Ucr6gJ_B5DY
You can skip the first part of his presentation and go directly to time marker 3:46 where he starts talking about 250.92 (A) & (B).
I did a web search to check his credentials.
https://www.electricalcodeacademy.net/founder
.
Inspector #2 is clueless. If he does not understand the requirements of 250.92 he should not be an electrician let alone an inspector.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
1) The bold answer is correct, a bonding jumper on one end of the raceway would make it compliant.
2) The bold is incorrect, since the raceway has SEC's in it the requiment for bonding is by a means other than standard locknuts. If there are no concentric or eccentric KO's then a bonding locknut will suffice.
Sorry about that. On the day of the shut down someone from the shop showed with two electricians that were there to do the cut over from the old service electrical panel to the new electrical service electrical panel, while the POCO was there doing their thing outside. My friend said the guy from the shop was there maybe 20 minutes or or so and then left.
I called my friend that morning and asked if the electrician was going to correct the first electrician's screw up, (using the word electrician loosely). He said yes the electrician told him he had spent an hour earlier that morning at an electrical wholesale house looking for, what I thought he was talking about an aluminum bus bar to install in place the painted steel plate. (That would have met code.)
Turns out the steel plate was removed along with the double barrel mechanical lugs. Gone from the jobsite.... Just a guess the guy from the shop took it back with him, to the shop.
What the electrician replaced the steel plate, and two double barrel mechanical lugs with was a common neutral assembly Kit. Parallel feed through lugs are stacked on top of one another. Factory bonding strap bolted to the top of the assembly and bonded to the back of the switch enclosure. The electrician didn't remove paint from the enclosure, and secured the bonding strap to the enclosure with a #8 truss head self tapping sheet metal screw. I gotta redo that.
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1) Agree.
But what about the CT cabinet and supply side conductors RMC risers? They need to be bonded to the grounded conductor as well don't they? The way I read the code the supply side grounded conductor can be bonded to the CT enclosure. Or grounding bushings or grounding locknuts installed on that CT cabinet side of the raceway(s) that is connected to the main switch enclosure.
Dummy me I didn't get a good look at the neutral block assembly in the CT cabinet to see if maybe the electrician bonded it to the cabinet with a bonding strap or bonding screw. I would have noticed a bonding jumper wire though. It's padlocked shut now.
The #2 electrical inspector.
Not sure what I can diplomatically do there. I thought about calling the first electrical inspector that reads 250.92 (B) correctly and see if he would talk to the other inspector. I don't know if he would want to get involved though. Any ideas?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
When I built control panels I regularly used #8 truss head self-drilling/tapping screws that had standard machine threads and not the sheet metal type. Could that have been what was used? Of course the panel material needs to be thick enough.
I didn't remove the screw but the head of the screw looks exactly like this.
Everbilt #8 x 1/2 in. Phillips Modified Truss Head Zinc Plated Sheet Metal Screw (4-Pack) 815341 - The Home Depot
Sheet metal screws are an essential fastener for working with thinner metal. Sometimes used with fiberglass, wood, or plastic. These coarse threaded screws are available with a self tapping or self drilling
www.homedepot.com
kwired
Electron manager
- Location
- NE Nebraska
The gasket is supposed to be between the shoulder of fitting and the enclosure, though it won't last more than a year (if that) before sunlight and temp changes work on it and it no longer makes a good seal and eventually will crack and even disappear completely after cracking - leaving you with a loose and leaking fitting to enclosure joint - that reason alone I no longer use the gasket and still use the fitting in a myers hub even though technically they are not listed for anything but RMC/IMC.
The locknut is supposed to dig into the enclosure wall, possibly penetrating painted surfaces so that it can help assure bonding between the enclosure and fitting.
Raintight EMT fittings also have an additional nylon ferrule that the standard compression fittings don't have that is supposed to make the compression portion "rain tight". IMO all they do is make it a bigger PITA to insert the tubing, most the time you must take fitting completely apart or it hangs up on this ferrule trying to insert it, is worse in cold weather than warm weather as a general rule.
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Thinking about it again I'm pretty sure the neutral block in the CT cabinet is not bonded to the enclosure. Its mounted on the 3/4" plywood in the cabinet below the C phase CT. I know there was not a bonding jumper wire installed. I would have seen that.
The CT cabinet is not bonded to the grounded conductor as I see it. The only mechanical connection to the raceway is the 3" sealing locknuts that were used. That does not meet 250.92 (A)(2) or (B). Am I correct in my reading of the NEC?
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Thinking about it again I'm pretty sure the neutral block in the CT cabinet is not bonded to the enclosure. Its mounted on the 3/4" plywood in the cabinet below the C phase CT. I know there was not a bonding jumper wire installed. I would have seen that.
The CT cabinet is not bonded to the grounded conductor as I see it. The only mechanical connection to the raceway is the 3" sealing locknuts that were used. That does not meet 250.92 (A)(2) or (B). Am I correct in my reading of the NEC?
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texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
What does Electrical Code Academy have to do with this whole discussion?
You are correct, this does not comply with the code.
Carultch
Senior Member
- Location
- Massachusetts
Plywood sounds like an improvised component. I've never seen a manufacture use any wooden part inside a listed electrical product. It sounds like asking for a fire hazard to do that.
Usually these are mounted on a fiberglass or plastic standoff, so they are insulated from the enclosure. It is common that utilities require cold-sequence metering for CT cabinets being used instead of a self-contained meter, and therefore it is on the load side of the service disconnect, where neutral needs to be isolated from ground. As such, the manufacturers isolate the neutral as it comes from the factory, and have the option to bond the neutral if used in a hot-sequence application instead. For self-contained meter sockets, the opposite is true, as a bonded neutral is the default, and a separate accessory is needed to isolate it.
If it is cold sequence, the circuits in to and out of the CT cabinet would classify as feeders rather than service conductors, due to being on the load side of the service disconnect, and would only require bonding bushings if there is missing or impaired continuity of the box connections. It is hot sequence metering equipment, where service raceway bonding requirements would apply.
kwired
Electron manager
- Location
- NE Nebraska
If the CT cabinet is on POCO side of the "service point" then NEC doesn't apply to it and it is definitely not your problem what is inside there.
That said NESC that POCO's usually follow likely would still require the grounded conductor to be bonded to the cabinet.
3/4" plywood is a requirement of MIDAMERICAN ENERGY Co.
I always painted my plywood gray, both sides two coats. The Electrical Contractor that did this job left it unpainted.
Heck the first electrician that mounted the POCO's 3 CTs used #6 black, indoor use only, dry wall screws with small flat washers to support the CTs to the plywood. Those got changed out by the second electrician that took over the job.
Sequence is Meter, Switch, Fuse, (OCPD). Ct cabinet is on the supply side.
Probably the cheapest easiest way now is to bond the grounded conductor to the cabinet is to install a bonding jumper from the neutral block, (inside the CT cabinet), to the CT cabinet. I know the POCO made the first electrician change out what he had installed for the neutral block to the one required by the POCO. Hopefully it has a lug for a bonding jumper. Won't know until I can take a look inside.
If I can't bond the grounded conductor, neutral block assembly, to the CT cabinet then I will just install a bonding jumper from the CT cabinet to the main disconnect enclosure.
Can I meet code by running just one bonding jumper through one of the two 3" EMT supply side conductors raceways? Or just run it on the outside from one cabinet to the other? That won't look as pretty. (Sized per 250.102 (2))
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Just further validation for me after an AHJ electrical inspector told me I was wrong in my reading of 250.92 (B).
Paul Abernathy is one of the members of the CMP #5. Jmho, he is qualified to explain the meaning of 250.92 (A) and (B). I think he did a great job in his presentation on the subject matter.
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