I had an inspector leave me a message and said I couldn't use two single pole 20 amp breakers with a handle tie Can someone point me in the right direction of this code? Would this also apply to a wall heater circuit?
(1) Multiwire Branch Circuits. Individual single-pole circuit
breakers, with identified handle ties, shall be permitted
as the protection for each ungrounded conductor of multiwire
branch circuits that serve only single-phase line-to-neutral
loads.
Sounds like a "shirt pocket" rule to me. It's probably cheaper and faster to just install a 2-pole 20 amp than fight it.
The Inspector might be thinking that 240.15(B) prohibits what you have installed. I am not certain it does. But the thinking might be that a pair of single pole breakers with a handle tie would certainly allow manually opening both ungrounded conductors. But it might not work automatically. Assume a fault takes place in the line between one of the two breakers and the load. That breaker will see the high current and will trip internally. Current from the other breaker must first pass through the load, before reaching the fault point. That might not be enough current to cause the second breaker to trip. I don't know if one breaker's attempt to move its handle to the "trip free" position would pull the other breaker handle with it, and pull it far enough to take it to the "open" position. Keep in mind that you can't manually (including through the use of a handle tie) move a breaker from "on" to "trip free."
Take a look at 240.15(B) and sub articles 1-4.I had an inspector leave me a message and said I couldn't use two single pole 20 amp breakers with a handle tie Can someone point me in the right direction of this code? Would this also apply to a wall heater circuit?
I thought that was the whole point of handle ties??
And I though the point was to ensure that if you manually opened one, the other would open with it. Keep in mind that a breaker's trip mechanism is all internal to the breaker. The handle moves halfway to the open position, and can't be reclosed until it is first fully opened. I think it would take more force than the one breaker can supply in order to force the second breaker's handle to go fully open. Also keep in mind that if you installed some type of locking or blocking device that would forct a breaker's handle to remain in the fully closed position no matter what happens, the breaker will still trip (internally) on detecting a fault current.I thought that was the whole point of handle ties??
The Inspector might be thinking that 240.15(B) prohibits what you have installed. I am not certain it does. But the thinking might be that a pair of single pole breakers with a handle tie would certainly allow manually opening both ungrounded conductors. But it might not work automatically. Assume a fault takes place in the line between one of the two breakers and the load. That breaker will see the high current and will trip internally. Current from the other breaker must first pass through the load, before reaching the fault point. That might not be enough current to cause the second breaker to trip. I don't know if one breaker's attempt to move its handle to the "trip free" position would pull the other breaker handle with it, and pull it far enough to take it to the "open" position. Keep in mind that you can't manually (including through the use of a handle tie) move a breaker from "on" to "trip free."
(B) Circuit Breaker as Overcurrent Device. Circuit
breakers shall open all ungrounded conductors of the circuit
both manually and automatically unless otherwise permitted
in 240.15(B)(1), (B)(2), (B)(3), and (B)(4).
So fuses are prohibited as the OCPD for those types of circuits?It's a safety issue. The heater could trip one breaker, shutting it down, but still have 120V present, because the other breaker doesn't trip. If the breaker ever trips, both legs need to open, not just one leg.
In some cases tandem or quad breakers, with a common trip but more than one handle, will use a handle tie as a cosmetic feature to show that two of the poles in a tandem or quad are functionally related.Handle ties don't trip the adjacent breaker. It's only purpose is to force you to turn off both (or three with a three handle tie bar) breakers when used on a MWBC.
So fuses are prohibited as the OCPD for those types of circuits?
I've taken apart a Siemens three pole breaker with the bar that attached across all three handles to see if I could make a two pole breaker out of it. (yeah, yeah, modification, don't even go there. I was out of town with no supply houses anywhere nearby and I wanted to make it work). Much to my surprise, the breaker did have an internal trip lever that connected from breaker to breaker to breaker.In some cases tandem or quad breakers, with a common trip but more than one handle, will use a handle tie as a cosmetic feature to show that two of the poles in a tandem or quad are functionally related.
It is also possible that the internal common trip mechanism will not by itself prevent manual operation of one pole. The handle tie completes the functional linkage.
240.15(B)1 only allows listed handle ties for single pole breakers of a MWBC.
I forgot to add this quote with my post before, but 24015(B) clearly states:
(B) Circuit Breaker as Overcurrent Device. Circuit
breakers shall open all ungrounded conductors of the circuit
both manually and automatically unless otherwise permitted
in 240.15(B)(1), (B)(2), (B)(3), and (B)(4).
Handle ties don't trip the adjacent breaker. It's only purpose is to force you to turn off both (or three with a three handle tie bar) breakers when used on a MWBC.
That is the (B)(1) situation above.I see what you're saying. A service tech working on the equipment would know that shutting of the fused safety switch would open all ungrounded conductors. If you look closer at 240.15(B), it only applies to circuit breakers used for OCP.
I think the reason the handle tie rule was born because too many homeowners and handy people were getting blasted by open neutrals on MWBC.
Some are.An air conditioner is not a line to neutral load.
JAP>
Are the breakers labeled as comp ntrip?I had an inspector leave me a message and said I couldn't use two single pole 20 amp breakers with a handle tie Can someone point me in the right direction of this code? Would this also apply to a wall heater circuit?
Guessing comp ntrip is either a new term or is supposed to be common trip.Are the breakers labeled as comp ntrip?