Tapping off of a 240V dryer circuit for a 120V outlet: What section of the code?

Status
Not open for further replies.

ELA

Senior Member
Occupation
Electrical Test Engineer
Can someone please cite the section of code that would address the ability to tap off of an existing 240V dryer circuit to provide a 120V receptacle for auxiliary use?
Is there a section in the code that would disallow this? Understood that additional overcurrent protection would be required for the receptacle but is this even a possibility?
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Can someone please cite the section of code that would address the ability to tap off of an existing 240V dryer circuit to provide a 120V receptacle for auxiliary use?
Is there a section in the code that would disallow this? Understood that additional overcurrent protection would be required for the receptacle but is this even a possibility?

The rating of the OCPD would be too high for use on a 120V convenience receptacle. You could start with 210.3 for one of the reasons you can't do that.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Can someone please cite the section of code that would address the ability to tap off of an existing 240V dryer circuit to provide a 120V receptacle for auxiliary use?
Is there a section in the code that would disallow this? Understood that additional overcurrent protection would be required for the receptacle but is this even a possibility?

Didn't see this part in my previous post. If you were abandoning the dryer outlet you could change the OCPD and use the conductors for the 120V circuit. Of course the wires may be larger than some devices can handle. As far as adding OCPD for the 120V circuit, the only way to do that would be to set a sub panel, and feed the dryer and 120V outlets from that.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Didn't see this part in my previous post. If you were abandoning the dryer outlet you could change the OCPD and use the conductors for the 120V circuit. Of course the wires may be larger than some devices can handle. As far as adding OCPD for the 120V circuit, the only way to do that would be to set a sub panel, and feed the dryer and 120V outlets from that.

Why couldn't you just add a jbox with a fuse in it?

They used to make such a beast just for this kind of thing that fit in a 4x4 box.
 

kwired

Electron manager
Location
NE Nebraska
I don't believe there is a requirement for an electric clothes dryer to be on a single outlet circuit.

I don't see that there is a problem with this, except for current codes may require AFCI protection depending on where the outlet is that is being supplied. This can possibly still be accomplished however because up to the overcurrent device is not part of the branch circuit it is actually a feeder tap.

If you wish to operate whatever the new outlet is supplying along with the dryer, you could have a problem depending on how much load it is. I still don't see it as a code violation but rather a possible poor design.

I think a similar question has been posted before with a lot of debate over whether it is acceptable to do so or not.
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
I don't believe a branch circuit tap is allowed to supply a receptacle outlet per 210.19(4) ex. 1(c).

Also, the concept of tapping a branch circuit and supplying additional overcurrent protection doesn't sound right to me. That would make the original branch circuit both a branch circuit and a feeder at the same time, by definition.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
I don't believe there is a requirement for an electric clothes dryer to be on a single outlet circuit.

I don't see that there is a problem with this, except for current codes may require AFCI protection depending on where the outlet is that is being supplied. This can possibly still be accomplished however because up to the overcurrent device is not part of the branch circuit it is actually a feeder tap.

If you wish to operate whatever the new outlet is supplying along with the dryer, you could have a problem depending on how much load it is. I still don't see it as a code violation but rather a possible poor design.

I think a similar question has been posted before with a lot of debate over whether it is acceptable to do so or not.

I didn't say a dryer had to be a separate circuit. My point was if you spliced into the conductors for the dryer to supply a 120V circuit, the OCPD for the dryer (probably 30A) would be too large for a normal 15 or 20A general receptacle. That is unless you used one of the tap rules and I don't know which one would/could be applied here.
 

kwired

Electron manager
Location
NE Nebraska
I don't believe a branch circuit tap is allowed to supply a receptacle outlet per 210.19(4) ex. 1(c).

Also, the concept of tapping a branch circuit and supplying additional overcurrent protection doesn't sound right to me. That would make the original branch circuit both a branch circuit and a feeder at the same time, by definition.

Sorry but I just don't see that section prohibiting what we are talking about.

Why is it impossible for a circuit to be a feeder and a branch circuit?

I didn't say a dryer had to be a separate circuit. My point was if you spliced into the conductors for the dryer to supply a 120V circuit, the OCPD for the dryer (probably 30A) would be too large for a normal 15 or 20A general receptacle. That is unless you used one of the tap rules and I don't know which one would/could be applied here.

Any of the tap rules could possibly apply if the conditions of the rule are met.

Tap rule is not at question here, whether or not the circuit can have additional load connected to it is the question.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Can someone please cite the section of code that would address the ability to tap off of an existing 240V dryer circuit to provide a 120V receptacle for auxiliary use?
Is there a section in the code that would disallow this? Understood that additional overcurrent protection would be required for the receptacle but is this even a possibility?

Tap rule is not at question here, whether or not the circuit can have additional load connected to it is the question.

That may be what the OP meant but I don't see the specific question you stated in the OP. To me, it was a more of "can/should it be done" question.
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
Why is it impossible for a circuit to be a feeder and a branch circuit?

By definition, a feeder is all the conductors between the service equipment...and the final branch circuit overcurrent device. A branch circuit is the conductors between the final overcurrent device protecting the circuit and the outlets. They are mutually exclusive. A circuit can't be both.

Sorry but I just don't see that section prohibiting what we are talking about.

Branch circuit taps are only allowed to supply the loads listed in 210.19(A)(3) ex.1 and 210.19(A)(4) ex. 1. In this case, 210.19(A)(4) would apply. It says: "Tap conductors shall have an ampacity sufficient for the load served...and only where these tap conductors supply any of the following loads."
 

kwired

Electron manager
Location
NE Nebraska
By definition, a feeder is all the conductors between the service equipment...and the final branch circuit overcurrent device. A branch circuit is the conductors between the final overcurrent device protecting the circuit and the outlets. They are mutually exclusive. A circuit can't be both.

Does not have to be supplied by service equipment, again where does it say the circuit can not fit both definitions.

I could always put a loadcenter on the 30 amp circuit then feed the dryer and other receptacle with separate breakers, then there is no question what is feeder and what is branch circuit, but I don't see that anything says I have to do this either. If the dryer outlet has proper overcurrent protection why would it need a separate breaker supplying it?



Branch circuit taps are only allowed to supply the loads listed in 210.19(A)(3) ex.1 and 210.19(A)(4) ex. 1. In this case, 210.19(A)(4) would apply. It says: "Tap conductors shall have an ampacity sufficient for the load served...and only where these tap conductors supply any of the following loads."

The taps permitted in those sections also do not require overcurrent protection at the load end like a feeder tap does.

We are talking about providing proper overcurrent protection for what is fed by the tap, so we are creating a feeder tap.
 

renosteinke

Senior Member
Location
NE Arkansas
Warning: Contradictory opinions follow:

I believe that were you to do this, you would also have to place the dryer OCPD after the tap. At least, if you wanted to 'get technical.'

I base this guess on the construction of the old fuse boxes; 60 amp service with (usually) 60 amp fuses in the range fuse block ... which was located right next to the main fuses. Sure, one COULD use smaller fuses for the range .... and if I ever find someone who did, I'll be sure to take a picture of it!

This would tend to support the opinion that a circuit cannot be both feeder and branch.

Not to be too fussy, but are we not also supposed to size circuits to the load? Just how much 'extra power' is available on a dryer circuit? Certainly not the 15 amps a convenience receptacle circuit would require.

What about for a single receptacle, serving a specific load - such as a light? Or, a non-coincident load like an iron?

Finally, is there room in the box (conductor fill) for the splice?

The idea isn't all that unusual. Many appliances tap 120 off the 240; just look in the kitchen. Apart from the light in the oven, ranges once had fused receptacles on them.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
So is installing an inline fuse make half the circuit a feeder and the other half a branch circuit. I would call that supplemental OCP and still see this as a branch circuit. Art. 422.10(B) takes us to 210.23. IMO, a dryer is a fixed in place appliance and as such 210.23(A)(2) is appropriate. Now we can argue all day about whether a dryer is fixed but IMO, it is since it is left there and not intended to be moved- it is also connected to a dryer vent so it isn't exactly portable.
 

kwired

Electron manager
Location
NE Nebraska
Warning: Contradictory opinions follow:

I believe that were you to do this, you would also have to place the dryer OCPD after the tap. At least, if you wanted to 'get technical.'

I base this guess on the construction of the old fuse boxes; 60 amp service with (usually) 60 amp fuses in the range fuse block ... which was located right next to the main fuses. Sure, one COULD use smaller fuses for the range .... and if I ever find someone who did, I'll be sure to take a picture of it!

This would tend to support the opinion that a circuit cannot be both feeder and branch.

Not to be too fussy, but are we not also supposed to size circuits to the load? Just how much 'extra power' is available on a dryer circuit? Certainly not the 15 amps a convenience receptacle circuit would require.

What about for a single receptacle, serving a specific load - such as a light? Or, a non-coincident load like an iron?

Finally, is there room in the box (conductor fill) for the splice?

The idea isn't all that unusual. Many appliances tap 120 off the 240; just look in the kitchen. Apart from the light in the oven, ranges once had fused receptacles on them.

Most old fuse boxes were actually 100 amp rated. If you pull the main fuse block it kills everything except for the range pullout. There were some that were 60 amp - if you pulled the main everything is dead. I can't ever recall seeing one fed with anything but 6 AWG - usually SE cable.

How much extra power in a dryer circuit? Maybe more than most people realize. Most dryers are 5000-5500 watt. A 30 amp 240 volt circuit can deliver 7200 (non continuous load), of course you are only going to get half of that for a 120 volt circuit. If the load you are trying to supply is less than 5 amps 120 volt you may never have overload issues. Maybe this is acceptable for adding a light, small exhaust fan, or a dryer duct booster fan.
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Now hold on! I've seen the same done a thousand times on range outlets. Range outlet fused anywhere from 40 to 60 amps. A #12 or 14 NM tapped from hot & neutral to 120 volt recep. Sometimes even had ground too, also tapped to neutral, or to grnd if 4 wire outlet. Sometimes the new recept even had correct polarity. Now if a lot of people are doing such things, it must be OK, right? After all, no one out there would do unsafe or illegal work.:D
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
The taps permitted in those sections also do not require overcurrent protection at the load end like a feeder tap does.

That is correct, because a branch circuit is the conductors between the FINAL overcurrent protective device and the outlets. That is why branch circuit taps are not required to terminate at an OCPD like feeder taps do.

We are talking about providing proper overcurrent protection for what is fed by the tap, so we are creating a feeder tap.

You cannot "create" a feeder tap from a branch circuit. The dryer circuit is a branch circuit. A branch circuit must be tapped in accordance with 210.19(A)(3) and (4).

A feeder must be tapped in accordance with 240.21(B). 240.21(B) says "Conductors shall be permitted to be tapped, without overcurrent protection at the tap, to a FEEDER as specified in 240.21(B)(1) thru (B)(5)."

You could take the existing dryer branch circuit and provide a new branch overcurrent device near the dryer, thereby making the circuit from the panel to the new branch OCPD a feeder, and then tap the feeder. But as described, tapping a branch circuit to feed a receptacle, that is not permitted by code.
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
Now hold on! I've seen the same done a thousand times on range outlets. Range outlet fused anywhere from 40 to 60 amps. A #12 or 14 NM tapped from hot & neutral to 120 volt recep. Sometimes even had ground too, also tapped to neutral, or to grnd if 4 wire outlet. Sometimes the new recept even had correct polarity. Now if a lot of people are doing such things, it must be OK, right? After all, no one out there would do unsafe or illegal work.:D

I don't see anything in 210.19(A)(3) which prevents a tap from a range branch circuit from feeding a receptacle outlet. But the dryer circuit tap would fall under 210.19(A)(4), not (A)(3).
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
So is installing an inline fuse make half the circuit a feeder and the other half a branch circuit. I would call that supplemental OCP and still see this as a branch circuit.

If the fuse is intended to protect the circuit conductors then it is not a Supplementary OCPD. A Supplementary OCPD is a device intended to provide limited overcurrent protection for specific applications and utilization equipment such as luminaires and appliances.

Per 240.21, a supplementary OCPD shall not be used as a substitute for required branch circuit OCPDs, or in place of the required branch circuit protection. You can't create a new branch circuit from an existing branch circuit.
 

kwired

Electron manager
Location
NE Nebraska
How about this situation:

120 volt 20 amp branch circuit feeding receptacle outlets, 12 AWG conductor. We decide we want to add a lighting outlet but for whatever reason we want to use 14 AWG conductor, so we come from one of the receptacle outlets to a 15 amp breaker and continue on with 14 AWG for the lighting outlet, switch(es) etc. Is this allowed by NEC or not, assuming it is not a SABC or some other dedicated circuit that would otherwise prohibit the lighting outlet even if it were supplied with 12 AWG.

Kind of the same thing as the tap from the dryer circuit.

I myself would prefer to just run 12 AWG conductor - it likely will cost less than the breaker and panel for just a small amount of 12 vs 14, but I also see no problem with the idea.
 
Status
Not open for further replies.
Top