Yes indeed in a remote building or structure environment…but not when within the same dwelling…that is where you run into the “Remote Distribution Panel” with MLO terminations in many cases…and is generally where some get confused…since the feeders can be protected at the main panel…and only branch circuits from the remote distribution panel require OCPD’s at that panelboard and enclosure.
GFCIs are not overcurrent devices and they will not reliably open in a bolted fault. Quite often it simply destroys the GFCI (shorted). If you do trip a breaker on a GFCI circuit, be sure to test the GFCI when you restore power. It may not work.
BUT it is important to know that a GFCI Breaker is indeed an OCPD as well…it serves as both ( that was my shameless plug for Eaton® )
True Paul, sorry I was referring to the “device” unit.
It is just the relay they use in the device that can’t deal with a bolted fault. The breaker style actually ends up tripping the breaker contact that is rated for AFC.
http://members.aol.com/gfretwell/gfci.jpg
OK, now I *am *confused.
We have:
“Where more than one building or other structure is on the same property and under single management, each additional building or other structure that is served by a branch circuit or feeder on the load side of the service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E).”
And we have:
“ a multiwire circuit can be installed to a detached garage as long as there is a disconnect that is rated as service equipment installed at the garage.
Article 225 was introduced to the NEC in the early 1970s and the requirement for a disconnect was entered in the 1993 code cycle, 225-8 with 225-8© requiring the disconnect to be rated as service equipment.”
*“today’s code (2005) 225.36 has an exception which states;
Exception: For garages and outbuildings on residential property, a snap switch or a set of 3-way or 4-way snap switches shall be permitted as the disconnecting means.
What we need to understand is that the part of this exception that limits the use of these switches is “A snap switch” and “**A **set of 3-way or 4-way snap switches” which clearly denotes a single switch or a single set of 3-way or 4-way switches.
If only a single disconnect means is allowed at the garage, how can we have multi-wire circuits (say, for outlets and lighting) run to it?
When running electricity to a remote building on the same property there are several rules that apply to the circuit(s).
When I say remote building I am including everything from pump houses, out buildings and detached garages all the way up to and including separate industrial buildings.
Any building that is remote to the one on which the service is attached is required to have a disconnecting means installed. In residential applications this disconnecting means is allowed to be a snap switch or a set of three ways when only one circuit is installed.
In 225.39 the size of the circuit supplying the remote building is mandated to be one of these;
- For installations to supply only limited loads of a single branch circuit, the branch circuit disconnecting means shall have a rating of not less than 15 amperes.
- For installations consisting of not more than two 2-wire branch circuits, the feeder or branch-circuit disconnecting means shall have a rating of not less than 30 amperes.
- If the remote building is a dwelling, the feeder disconnecting means shall have a rating of not less than 100 amperes, 3-wire.
- For all other installations, the feeder or branch-circuit disconnecting means shall have a rating of not less than 60 amperes.
225.30 requires that each additional building or other structure that is served by a branch circuit or feeder on the load side of the service disconnecting means shall be supplied by only one feeder or branch circuit.
225.31 Disconnecting Means.
Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
225.36 Suitable for Service Equipment.
The disconnecting means specified in 225.31 shall be suitable for use as service equipment.
It is here that we find the exception for switches. Pay attention to the “A” which is a singular switch or set of three ways with a four way in the middle.
Exception: For garages and outbuildings on residential property, a snap switch or a set of 3-way or 4-way snap switches shall be permitted as the disconnecting means.
It doesn’t matter if it is a single 120 volt circuit or a multiwire circuit the requirement to have some way of disconnecting all ungrounded conductors must be installed at this remote building.
If it is a multiwire circuit and the multiwire circuit is broke into two separate circuits in this building such as lights and receptacles then the disconnecting means is required to be rated at 30 amps.
To install two 120 volt two wire branch circuits, one for the lights and the other for the receptacles is a violation of 225.30. Installing a 240 volt multiwire circuit and splitting it in the building without a disconnect is a violation of 225.31.
The safety issues are; should something go wrong in this remote building there needs to be an accessible means to open all hot conductors in a hurry instead of running around trying to find a remote panel and then figuring out just what turns the power off.
Does this help?
A multiwire circuit is still considered one circuit and you disconnect it with a 2 pole switch as a general rule. I suppose you could use 2 single pole switches in a dwelling if there are no 240v loads and no shared device yokes.
This is where I’m starting to get confused, the case I was thinking of was a multiwire (three wire) with two 120V circuits on a shared neutral (say, on for lights, and one for outlets) originating at a two-pole breaker at a service or load-side panel in the main structure…
Perhaps we can back up a step:
-
The circuit to the garage can be a single 120V circuit, with the OCPD at a service or load side panel in the main structure.
-
The circuit to the garage cam be feeders to load-side panel at the garage, from a service or load side panel at the main structure.
-
The circuit(s) to the the garage can also be ??? (if anything).
Once I understand if these is - or is not -a third case, I will have an easier time understanding the disconnect requirements.
- The garage can also
Being that this is supplying two circuits the disconnect at the garage will be required to be not less than 30 amps. There is no such thing as a 120 volt multiwire circuit.
And the disconnect located at the garage can be a single pole switch or a set of three ways with one three way at the garage and the other at the house. The switch(es) must turn off all power going to the garage.
Feeders can land in a panel at the garage as long as the panel is rated as service equipment or they can land in a disconnect such as a disconnect with fuses as long as the disconnect is rated as service equipment.
Any circuit at the detached garage must have something to disconnect the circuit from the garage.
In all cases a means to disconnect all the hot conductors MUST be installed.
be required to have a grounding electrode installed 250.32
A multiwire circuit could be opened with a two pole switch as long as it is an individual branch circuit supplying only one circuit.
The use of two single pole switches will not work at the house due to 225.31 and they will not work at the detached garage due to 225.30, and 225.39.
225.33(B) Single-Pole Units. Two or three single-pole switches or breakers capable of individual operation shall be permitted on multiwire circuits, one pole for each ungrounded conductor, as one multipole disconnect, provided they are equipped with handle ties or a master handle to disconnect all ungrounded conductors with no more than six operations of the hand.
It is language like this in the NEC that makes you shake your head.
They say you can use up to 3 single pole switches (assuming up to 3p wye)… then they say handle ties … then they say no less than six operations. It seems to me 2 single pole switches without handle ties only requires 2 operations.
Since you can’t have more than one circuit (a multiwire is one) I don’t see any case where a multiwire can’t be single pole switches unless you have the 240v load or land on a single yoke.
All that said I still like to see the 2 pole switch and that is what I always got.
Greg
What will stop the use of two single pole switches at the remote building is;
225.36 Suitable for Service Equipment.
The disconnecting means specified in 225.31 shall be suitable for use as service equipment.
Exception: For garages and outbuildings on residential property, a snap switch or **a set of 3-way **or 4-way snap switches shall be permitted as the disconnecting means.
Here it is clear that the switches must be singular.
To use the single pole breakers in a main lug panel then the panel would be required to be suitable for use as service equipment and no one makes a panel that is suitable for use as service equipment using single pole breakers,
I agree that is the intent but you keep bumping up against that “6 throw” language.
I think we both agree the NEC is poorly coordinated in this and other areas where they use conflicting language.
I guess if it was easy to understand we wouldn’t need ongoing education and the instructors would be largely out of business. The “churn” generated by a 3 year code cycle is also part of the problem.