using three wire for branch cicuits

Status
Not open for further replies.

tmason

Member
im a new jersy electrictian i have a question concerning a 14-3 wire that was previously used as two circuits in a panel that i changed. i needed room in the paniel so i took a 14-3 circuit that i ohm out the black had 5 amps and the red had 4 i twited the two wires togeather and put one tail to a single 15 amp breaker is that legal or is it not im be told that you cant do that because its a inbalenced load could some one please help me and if you could verse and chapter would be great
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
You're fine to a point in that this, is no longer a a MWBC, it is simply a two wire circuit. The problem I have is that you didn't identify what the circuits were supplying. Putting an ohm meter on these conductors really doesn't mean much, loads change when they are energized.

Roger
 

tmason

Member
those readings were with the loads so are you saying this is permissible under th nj nec if so would you know the verse and chapter
 

tmason

Member
so are you saying that it is acceptible under the nj nec and would you happen to know verse and chapter
 

Mr 3phase

Member
I may be wrong, but as I understand it, the UL listing for an overcurrent device (breaker) is on the basis that only one branch circuit is to be terminated on one overcurrent device. If in fact you have spliced two wires on to one and terminated it on one OCD, you may have voided the UL listing. Why wouldn't you use a 'tandem' breaker and maintain two separate branch circuits? ( I am assuming the panel is listed for tandem breakers).
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
those readings were with the loads so are you saying this is permissible under th nj nec if so would you know the verse and chapter

Then let me ask, did you mean to say you put an ammeter on these circuits in your opening post? By saying you put an ohmmeter on them leads us to believe you're just applying ohms law to your readings.

Roger
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't see an issue with it at all. It is not a MWBC as pointed out since you moved the wire to the same phase. If the load is sufficient then it is good, IMO.

I assume you meant you used an amp meter not a ohm meter when you got 5 amps and 4 amps. :grin:
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
so are you saying that it is acceptible under the nj nec and would you happen to know verse and chapter
Unless NJ has ammended the NEC, there is nothing prohibiting splicing these conductors in the panel and making a single two wire circuit.

Roger
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
I may be wrong, but as I understand it, the UL listing for an overcurrent device (breaker) is on the basis that only one branch circuit is to be terminated on one overcurrent device.
And that is all you have, one branch circuit
If in fact you have spliced two wires on to one and terminated it on one OCD, you may have voided the UL listing.
No you haven't and regardless, the listing information wouldn't care how the field wiring was done.
Why wouldn't you use a 'tandem' breaker and maintain two separate branch circuits? ( I am assuming the panel is listed for tandem breakers).
Because you don't have to, and in fact some manufacturers small breakers are listed and identified for use with two conductors but that is not what you said you did.

Roger
 

Barndog

Senior Member
Location
Spring Creek Pa
I may be wrong, but as I understand it, the UL listing for an overcurrent device (breaker) is on the basis that only one branch circuit is to be terminated on one overcurrent device. If in fact you have spliced two wires on to one and terminated it on one OCD, you may have voided the UL listing. Why wouldn't you use a 'tandem' breaker and maintain two separate branch circuits? ( I am assuming the panel is listed for tandem breakers).

You still only have one wire under the breaker. it would be like putting a 4 square right out of the panel and spliceing two wires there. are you saying that isnt allowed??
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I may be wrong, but as I understand it, the UL listing for an overcurrent device (breaker) is on the basis that only one branch circuit is to be terminated on one overcurrent device.
A simple pigtail and wirenut will solve that.

If in fact you have spliced two wires on to one and terminated it on one OCD, you may have voided the UL listing. Why wouldn't you use a 'tandem' breaker and maintain two separate branch circuits? ( I am assuming the panel is listed for tandem breakers).
Because, with two separate breakers on the same phase (line), the shared neutral could be overloaded. By sharing one 15a breaker, the grounded conductor is still protected at its ampacity.

That's probably the most overlooked issue when tandem breakers are used.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
so are you saying that it is acceptable under the NJ NEC and would you happen to know verse and chapter
The only thing left to consider is what the old wiring supplies.

You haven't told us whether this branch circuit is in a dwelling, or not. If it is in a dwelling, one needs to consider the type of load that is supplied. At the simplest, if the old multiwire branch circuit covered only "general lighting load" and is given 15 Amp overcurrent protection, the square foot area that the circuit can supply, as you have it hooked up now, has been cut in half from 1200 square feet to 600 square feet.

There are more points to raise along this line of thinking (and Code referenced concerns), but, instead of trying to speak to every case that "might" be the one, please tell us what the outlets are that are on that old multiwire branch circuit that you consolidated.

You told us what you measured the amps to be, but what are the outlets . . . how many, what type, any hardwired equipment, etc.?
 
Last edited:

tmason

Member
A simple pigtail and wirenut will solve that.

Because, with two separate breakers on the same phase (line), the shared neutral could be overloaded. By sharing one 15a breaker, the grounded conductor is still protected at its ampacity.

That's probably the most overlooked issue when tandem breakers are used.

Mr fine are you saying that as long as you pig tail the two wires its fine and if so would you know the verse and chapter in the code
 

tmason

Member
The only thing left to consider is what the old wiring supplies.

You haven't told us whether this branch circuit is in a dwelling, or not. If it is in a dwelling, one needs to consider the type of load that is supplied. At the simplest, if the old multiwire branch circuit covered only "general lighting load" and is given 15 Amp overcurrent protection, the square foot area that the circuit can supply, as you have it hooked up now, has been cut in half from 1200 square feet to 600 square feet.

There are more points to raise along this line of thinking (and Code referenced concerns), but, instead of trying to speak to every case that "might" be the one, please tell us what the outlets are that are on that old multiwire branch circuit that you consolidated.

You told us what you measured the amps to be, but what are the outlets . . . how many, what type, any hardwired equipment, etc.?

To the best dicription from disconnecting the power to both wires it was some lights and outlets in closets and attic that would not constatute a big load
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Mr fine are you saying that as long as you pig tail the two wires its fine and if so would you know the verse and chapter in the code
It's not prohibited. There's no electrical difference between one circuit being split in a J-box and one being split in the panel.
 

tmason

Member
It's not prohibited. There's no electrical difference between one circuit being split in a J-box and one being split in the panel.

Would you happen to know the verse and chapter and so i know the correct term it would be prohibbited if i put the wires on two different brk on the same phase this would give you a unbalenced load on the neutral correct
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
To the best dicription from disconnecting the power to both wires it was some lights and outlets in closets and attic that would not constatute a big load
It's not a question of it being a "big load", it's a question of Code.

As you call this "some lights and outlets in closets and attic" I first infer that this is a dwelling.

Is it a standalone single family dwelling?

Second, I infer that you are describing receptacles, lights and other outlets that are only General Lighting Load. A dwelling general lighting load is calculated at 3 Watts per square foot of habitable floor space. The dimensions used to calculate the square feet are from measurements taken on the outside of the walls.

3 Watts / sq. ft. x 600 sq. ft. = 1800 Watts (which is the let through of a 15 Amp breaker) . . . . see how that works?
 

tmason

Member
It's not a question of it being a "big load", it's a question of Code.

As you call this "some lights and outlets in closets and attic" I first infer that this is a dwelling.

Is it a standalone single family dwelling?

Second, I infer that you are describing receptacles, lights and other outlets that are only General Lighting Load. A dwelling general lighting load is calculated at 3 Watts per square foot of habitable floor space. The dimensions used to calculate the square feet are from measurements taken on the outside of the walls.

3 Watts / sq. ft. x 600 sq. ft. = 1800 Watts (which is the let through of a 15 Amp breaker) . . . . see how that works?


im up to date with that calculation but the issue is im being told that by splicing the two togeather you would have an unbalenced load on the neutral that is not possible as you would have one hot and one neutral so would it be a violation to splice the two togeather and tail it to a single 15 amp brk with one tail
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Would you happen to know the verse and chapter and so i know the correct term it would be prohibbited if i put the wires on two different brk on the same phase this would give you a unbalenced load on the neutral correct
The NEC is mostly about what is not allowed.

When two conductors share a neutral, the current is additive when both lines are on the same phase, and subtractive when they aren't.
 

Mr 3phase

Member
A simple pigtail and wirenut will solve that.

Because, with two separate breakers on the same phase (line), the shared neutral could be overloaded. By sharing one 15a breaker, the grounded conductor is still protected at its ampacity.

That's probably the most overlooked issue when tandem breakers are used.

I stand corrected...what I meant to say was : Install a tandem breaker and put one wire of the multi wire branch circuit under on breaker of the 'tandem'. Put another wire of a 'different circuit' under the other tandem. Then put the last wire of the multi wire circuit on its own breaker. No phase issues and eveything has its own OCPD.
 
Status
Not open for further replies.
Top