Power to Garage
- Thread starter Duuuuug
- Start date
- Status
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: Power to Garage
See 225, part II. If your disconnect complies, then "no."
See 225, part II. If your disconnect complies, then "no."
jwelectric
Senior Member
- Location
- North Carolina
Re: Power to Garage
This is so simple that I have a hard time understanding the confusion of others.
If this is a detached garage then the rules of 225 apply. If the garage is attached to the dwelling then it is just another sub panel. I will approach it as a detached garage with outside feeders.
225.30 Number of Supplies shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E).
For a dwelling unit the only one that is likely to be used would be (A) (4) Optional standby systems
225.31 Disconnecting Means. Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
A disconnect will be required
225.32 Location. The disconnecting means shall be installed either inside or outside of the building?.. shall be at a readily accessible location nearest the point of entrance
The disconnect can be on the inside or outside and this is not a tower or pole and will not be monitored be a qualified person so the exceptions will not apply.
225.33 Maximum Number of Disconnects. (A) General. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard.
Most dwellings will not have a shunt trip nor magnetic relay so the exception will not apply
(B) Single-Pole Units. Two or three single-pole switches or breakers capable of individual operation shall be permitted?.. with handle ties or a master handle
225.34 Grouping of Disconnects. (A) General. The two to six disconnects as permitted in 225.33 shall be grouped.
They are in the same panel so they are grouped and I don?t think that any part of (B) will apply
225.35 Access to Occupants. I don?t think this will apply
225.36 Suitable for Service Equipment. The disconnecting means specified in 225.31 shall be suitable for use as service equipment.
Make sure that it is rated ?suitable for use as service equipment.?
This in no way implies that this a service just that it is rated
225.37 Identification. just the one feeder so nothing here applies
225.38 Disconnect Construction. (A) it will probably work by hand (B) must open all hot conductors, (C) The neutral will land under a lug and this will comply, (D) must say weather it is on or off
225.39 Rating of Disconnect. only (D) will apply due to the rating you have given.
225.40 Access to Overcurrent Protective Devices. Make sure that access to the OCPD is available
Summary
As long as the feeder is protected at the point of origin and the panel has no more than six movements of the hand you have complied with 225.
This is so simple that I have a hard time understanding the confusion of others.
If this is a detached garage then the rules of 225 apply. If the garage is attached to the dwelling then it is just another sub panel. I will approach it as a detached garage with outside feeders.
225.30 Number of Supplies shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E).
For a dwelling unit the only one that is likely to be used would be (A) (4) Optional standby systems
225.31 Disconnecting Means. Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
A disconnect will be required
225.32 Location. The disconnecting means shall be installed either inside or outside of the building?.. shall be at a readily accessible location nearest the point of entrance
The disconnect can be on the inside or outside and this is not a tower or pole and will not be monitored be a qualified person so the exceptions will not apply.
225.33 Maximum Number of Disconnects. (A) General. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard.
Most dwellings will not have a shunt trip nor magnetic relay so the exception will not apply
(B) Single-Pole Units. Two or three single-pole switches or breakers capable of individual operation shall be permitted?.. with handle ties or a master handle
225.34 Grouping of Disconnects. (A) General. The two to six disconnects as permitted in 225.33 shall be grouped.
They are in the same panel so they are grouped and I don?t think that any part of (B) will apply
225.35 Access to Occupants. I don?t think this will apply
225.36 Suitable for Service Equipment. The disconnecting means specified in 225.31 shall be suitable for use as service equipment.
Make sure that it is rated ?suitable for use as service equipment.?
This in no way implies that this a service just that it is rated
225.37 Identification. just the one feeder so nothing here applies
225.38 Disconnect Construction. (A) it will probably work by hand (B) must open all hot conductors, (C) The neutral will land under a lug and this will comply, (D) must say weather it is on or off
225.39 Rating of Disconnect. only (D) will apply due to the rating you have given.
225.40 Access to Overcurrent Protective Devices. Make sure that access to the OCPD is available
Summary
As long as the feeder is protected at the point of origin and the panel has no more than six movements of the hand you have complied with 225.
- Location
- Illinois
- Occupation
- retired electrician
Re: Power to Garage
Mike,
Just to stir the pot a bit.
Don
Mike,
Just to stir the pot a bit.
If the individual breaker is the "disconnect" then the breaker must be rated at 60A or more.
Don
jwelectric
Senior Member
- Location
- North Carolina
Re: Power to Garage
Where is the confusion? It does not say the panel that is being supplied is required to have a single disconnect rated at not less than 60 amps.
If this was the case then all of the sections describing the six disconnect rule would be redundant.
If the FEEDER is protected at the point of origin then the FEEDER disconnect is in compliance.
Where is the confusion? It does not say the panel that is being supplied is required to have a single disconnect rated at not less than 60 amps.
If this was the case then all of the sections describing the six disconnect rule would be redundant.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Power to Garage
The confusing part comes from an unfortunate selection of words in 225.39. It is not as clear as one might wish, but I think it is not talking about this:
But I also think that the intent is to make sure the "other building" has enough power to handle its loads. So if the MLO panel as a whole is rated at least 60 amps, and if the sum total of the 6 breakers is at least 60 amps (hard to imagine this not happening), then I think it would satisfy 225.39.
The confusing part comes from an unfortunate selection of words in 225.39. It is not as clear as one might wish, but I think it is not talking about this:
In the house, and probably in the main panel, there will be a breaker that protects the feeder conductors leading to the garage. That is the "feeder disconnect" to which you refer. But I think 225.39 is saying that it is the disconnect (or set of up to 6 disconnects) located at the garage, and not the one inside the house, that must have a rating of 60 amps or more. Throughout 225, it is talking about the disconnect(s) that serve(s) the garage, and it means the one(s) just outside the garage or inside the garage. So Don's stirring of the pot was to inquire whether each of the six breakers (serving as the disconnects for the garage) must be at least 60 amps.
But I also think that the intent is to make sure the "other building" has enough power to handle its loads. So if the MLO panel as a whole is rated at least 60 amps, and if the sum total of the 6 breakers is at least 60 amps (hard to imagine this not happening), then I think it would satisfy 225.39.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Power to Garage
Originally posted by dillon3c:
jwelectric
Senior Member
- Location
- North Carolina
Re: Power to Garage
It is my opinion that 225.39 is talking about the disconnecting means for the feeder or branch circuit that is supplying the ?Building or Other Structure? as pointed out in the first sentence.
A disconnect for a feeder or branch circuit would go where?
Would it be at the place of origin or on the load side of the conductors?
Can I protect my receptacles (general purpose circuit) by placing the disconnect (OCPD) at the end of the circuit?
In the subsections we are told that if we run a single branch circuit that this circuit is required to be protected by 15 amp and should we run a two conductor multiwire circuit it must be protected by not less than 30 amps. This also tells that a twenty amp multiwire circuit is not allowed.
A dwelling unit must be supplied by no less than 100 amps and anything else must be no less than a 60 amp circuit.
In each of (A) through (D) it talks about the supply circuit and not the load side disconnect.
Would I be allowed to tap these unprotected from the service and place the OCPD at the end of the circuit?
The load side disconnect comes after the branch circuit or feeders. The feeder disconnect comes at the origin of the feeder.
I do not see the words appliance and lighting panelboard nor power panelboard or even outlet, appliance and device.
If I am wrong please show me where.
Edited for grammer
[ September 26, 2005, 02:39 PM: Message edited by: jwelectric ]
It is my opinion that 225.39 is talking about the disconnecting means for the feeder or branch circuit that is supplying the ?Building or Other Structure? as pointed out in the first sentence.
It states that this disconnecting means is for the feeders or branch circuits. These feeders or branch circuits will be calculated by 220.
A disconnect for a feeder or branch circuit would go where?
Would it be at the place of origin or on the load side of the conductors?
Can I protect my receptacles (general purpose circuit) by placing the disconnect (OCPD) at the end of the circuit?
In the subsections we are told that if we run a single branch circuit that this circuit is required to be protected by 15 amp and should we run a two conductor multiwire circuit it must be protected by not less than 30 amps. This also tells that a twenty amp multiwire circuit is not allowed.
A dwelling unit must be supplied by no less than 100 amps and anything else must be no less than a 60 amp circuit.
In each of (A) through (D) it talks about the supply circuit and not the load side disconnect.
Would I be allowed to tap these unprotected from the service and place the OCPD at the end of the circuit?
The load side disconnect comes after the branch circuit or feeders. The feeder disconnect comes at the origin of the feeder.
I do not see the words appliance and lighting panelboard nor power panelboard or even outlet, appliance and device.
If I am wrong please show me where.
Edited for grammer
[ September 26, 2005, 02:39 PM: Message edited by: jwelectric ]
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Power to Garage
This isn't about "branch circuits," per 210, nor about "feeders," per 215. It's about "outside branch circuits and feeders," per 225. The first two will tell you about protecting the wires from the house to the garage. 225 is talking about the disconnecting means at the garage itself. As I implied above, the wording of 225.39 was chosen poorly, in that it does not tell the world that I am right and you are wrong. So I am forced to admit that you might be right too.
This isn't about "branch circuits," per 210, nor about "feeders," per 215. It's about "outside branch circuits and feeders," per 225. The first two will tell you about protecting the wires from the house to the garage. 225 is talking about the disconnecting means at the garage itself. As I implied above, the wording of 225.39 was chosen poorly, in that it does not tell the world that I am right and you are wrong.
So I am forced to admit that you might be right too.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Power to Garage
225.39 is not talking about "overcurrent protection." It is talking about "a disconnecting means." I know you are not trying to pass these two off as being interchangeable. But the fact that they are not interchangeable helps support my case.
- Location
- Massachusetts
Re: Power to Garage
225.31 through 225.39 all have to do with the disconnecting means.
225.32 tells us the location is at the building served. It is not at the point of origin
This is still a 'feeder' disconnect even if it is at the far end of the feeder.
Remember that the rules for services closely mirror the rules for feeders to separate buildings.
What 'end' of the service conductors do we locate the service disconnect?
We call it a service disconnect but it does not kill the power to the service conductor it only disconnects the service conductors from the premises wiring system.
The same applies for feeders to separate buildings, the feeder disconnect disconnects the feeder from the building.
Stickily speaking there is no requirement to have a disconnect for the feeder at the point origin.
[ September 26, 2005, 04:40 PM: Message edited by: iwire ]
I often have the same problem trying to understand your view.
225.31 through 225.39 all have to do with the disconnecting means.
225.32 tells us the location is at the building served. It is not at the point of origin
This is still a 'feeder' disconnect even if it is at the far end of the feeder.
Remember that the rules for services closely mirror the rules for feeders to separate buildings.
What 'end' of the service conductors do we locate the service disconnect?
We call it a service disconnect but it does not kill the power to the service conductor it only disconnects the service conductors from the premises wiring system.
The same applies for feeders to separate buildings, the feeder disconnect disconnects the feeder from the building.
Stickily speaking there is no requirement to have a disconnect for the feeder at the point origin.
[ September 26, 2005, 04:40 PM: Message edited by: iwire ]
jwelectric
Senior Member
- Location
- North Carolina
Re: Power to Garage
Once again we stand in almost agreement except for a couple of details.
1) What is a feeder?
Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.
2) What is a branch circuit?
Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
3) Does the 15 amp circuit outlined in 225.39 (A) require a disconnect at the second building if it only supplies a duplex receptacle
I stand my ground.
Once again we stand in almost agreement except for a couple of details.
1) What is a feeder?
Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.
2) What is a branch circuit?
Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
3) Does the 15 amp circuit outlined in 225.39 (A) require a disconnect at the second building if it only supplies a duplex receptacle
I stand my ground.
- Location
- Massachusetts
Re: Power to Garage
The idea IMO is to kill the power to the buildings wiring for safety or service.
Yes it does, if that duplex does not comply with 225.32.
The idea IMO is to kill the power to the buildings wiring for safety or service.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Power to Garage
Great idea but not required by the code! When you have a service disconnect, the main switch or breaker does not kill the power to the building either!
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Power to Garage
It kills power to everything except the box in which the disconnect is located, and everything upstream (which should be outside the building). From the perspective of the fire fighter who is about to spray water all over the place (except, perhaps, right into the service disconnect itself), that building is de-energized. I think this is the reason that we can't install more than one service to a single building (except in very limited circumstances).
- Location
- Massachusetts
Re: Power to Garage
We both over looked something, a duplex would not meet the requirements of 225.36 or it's exception, so that duplex needs a disconnect which may be a snap switch.
mvannevel
Senior Member
- Location
- Hesperia, Michigan
Re: Power to Garage
Just as an example: I have a 100 ampere, 6 circuit, MLO panelboard located in a detached garage. I have a feeder protected in the service panel in the house by a 60 ampere breaker. In the garage I have 3 15 ampere circuits, one for the lighting (five lights total), one for three receptacles in one half and one for three receptacles in the other half (I like my garage circuits loaded lightly). I have no requirement to add a fourth 15 ampere circuit to total 60 amperes because it's not required by Article 225. I have 60 amperes of capacity in the garage, as is required by Article 225 because I have more than 2 circuits. And I have only 3 swipes of the hand required to disconnect the structure. In my opinion, a code compliant installation. In fact, it would be just as code compliant if I had one 15 ampere breaker, two 15 ampere breakers, or six 15 ampere breakers.
Remember, that requirement for the combined rating of the disconnects exists in Article 230 because we're talking about services, not feeders. Like Charlie said the intent here in Article 225 is to make sure that, if we have more than two 2-wire branch circuits, we have adequate capacity to handle the loads.
[ September 26, 2005, 07:59 PM: Message edited by: mvannevel ]
I agree with almost everything you say here except this:
230.80 says that where the disconnecting means for a service consists of more than one switch or circuit breaker, the combined ratings of all the switches or circuit breakers must not be less than the ratings in 230.79 (which mirror the requirements in 225.39). There is no parallel requirement for this in article 225. Which, if you think about it, makes perfect sense since we're talking about a feeder here instead of a service. We already have overcurrent protection ahead of the feeder conductors, so there's no need for the combined rating of the breakers serving as disconnecting means to total 60 amperes. Only that the enclosure that these disconnecting means are located in to be rated at least 60 amperes.
Just as an example: I have a 100 ampere, 6 circuit, MLO panelboard located in a detached garage. I have a feeder protected in the service panel in the house by a 60 ampere breaker. In the garage I have 3 15 ampere circuits, one for the lighting (five lights total), one for three receptacles in one half and one for three receptacles in the other half (I like my garage circuits loaded lightly). I have no requirement to add a fourth 15 ampere circuit to total 60 amperes because it's not required by Article 225. I have 60 amperes of capacity in the garage, as is required by Article 225 because I have more than 2 circuits. And I have only 3 swipes of the hand required to disconnect the structure. In my opinion, a code compliant installation. In fact, it would be just as code compliant if I had one 15 ampere breaker, two 15 ampere breakers, or six 15 ampere breakers.
Remember, that requirement for the combined rating of the disconnects exists in Article 230 because we're talking about services, not feeders. Like Charlie said the intent here in Article 225 is to make sure that, if we have more than two 2-wire branch circuits, we have adequate capacity to handle the loads.
[ September 26, 2005, 07:59 PM: Message edited by: mvannevel ]
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