detached garage and 3 way switches

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bguzz50

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I have a detached garage that is being fed by 2-2-4AL to a subpanel and has 2 grounding electrodes. Bus is bonded. Inspector has told me that it is acceptable to run #14 THWN via PVC conduit (then to romex)to the house for 3 sets of 3 way switches for the 3 garage exterior lights.

I had run 6 #14 wires already and he said I could use those as runners and pull hots from the house and ground to the house, and keep neutral in the garage.

I think this would violate 250.32 at least, or am I misinterpreting it?
 
Re: detached garage and 3 way switches

If the hot and neutral are not from the same panel, then you have a violation of 300.3(D).

I presume, from your statement that there is an N-G bond in the subpanel, that there is no EGC pulled from the house to the garage, and that there are no common metal piping systems between the two buildings. If that is true, you do not have a problem with 250.32. The problem is just with the proposed wiring of the light circuits.
 
Re: detached garage and 3 way switches

Yes, sub is bonded N-G.

Makes sense. If I pull additional #14's from the garage and use the garage EGC for the switches located in the house, I think I am safe and in code? Or could I pull additional #14's for the hot/switched hot, and runners and use the EGC in the house for the house switches?
 
Re: detached garage and 3 way switches

This thread had been placed on a temporarily "hold." This action was taken because the nature of the question and the occupation shown in the Original Poster's profile raised a concern that this may have been an attempt by a Do It Yourself person to obtain "how-to" information.

In an exchange of Private Messages, the Original Poster has provided assurances that he is a general contractor, and that the question is in line with the type of work he does for a living. Therefore, the thread has been reopened. I offer an apology to the OP for the inconvenience and the delay.
 
Re: detached garage and 3 way switches

If power for the lights at the garage is being supplied by a circuit or circuits from the house panel, then that/those circuits along with the feeder to the garage panel would constitute a violation of 225.30 IMO.
 
Re: detached garage and 3 way switches

Originally posted by eprice: If power for the lights at the garage is being supplied by a circuit or circuits from the house panel, then that/those circuits along with the feeder to the garage panel would constitute a violation of 225.30 IMO.
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I agree. You should have the power to the lights come from the garage panel. That includes the hots, the neutrals, and the grounds ? all should originate from the garage panel. I think it is acceptable to have wires (is it correct to call them "switch legs" or "runners"?) go from the garage to switches in the house, and back again to the garage. This would not violate the rule about more than one feeder to a separate building.

Without seeing a picture of what you plan to do with the switching, or without spending the time to invent a circuit myself, I don't think I can help you with how many wires need to go from one place to another. But since you are talking about #14 wires, may we conclude that the circuit breakers are all 15 amps?
 
Re: detached garage and 3 way switches

Originally posted by eprice:
If power for the lights at the garage is being supplied by a circuit or circuits from the house panel, then that/those circuits along with the feeder to the garage panel would constitute a violation of 225.30 IMO.
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See 225.30(D). A separate circuit for control of outside lighting from multiple locations is explicitly permitted.

This concept should work except for the neutral being hijacked. Either derive all wires for these circuits from the house panel and extend to the outbuilding, or derive them all from the outbuilding and extend them to the house.
 
Re: detached garage and 3 way switches

If you have 3-way switches with a switch in the house and switch in the garage you probably now have "continuous metallic paths bonded to the grounding system in both buildings". This assumes that the switches in the garage are grounded to the garage panel. If that is the case, then you will need to install agrounding conductor from the house to the garage and keep the neutrals and grounds separate in the garage panel.
 
Re: detached garage and 3 way switches

Originally posted by suemarkp:
Originally posted by eprice:
If power for the lights at the garage is being supplied by a circuit or circuits from the house panel, then that/those circuits along with the feeder to the garage panel would constitute a violation of 225.30 IMO.
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See 225.30(D). A separate circuit for control of outside lighting from multiple locations is explicitly permitted.

This concept should work except for the neutral being hijacked. Either derive all wires for these circuits from the house panel and extend to the outbuilding, or derive them all from the outbuilding and extend them to the house.
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So all wires from the garage would include the EGC (green wire) for the house switches also right?

[ December 01, 2005, 04:26 PM: Message edited by: bguzz50 ]
 
Re: detached garage and 3 way switches

Yes, that is what I am talking about. Sorry, I meant EGC. So my question is if the bottom EGC is connected to the garage ground (EGC), is this supported by 225.30(d)? Thanks for the diagram...makes it clearer.

[ December 01, 2005, 06:49 PM: Message edited by: bguzz50 ]
 
Re: detached garage and 3 way switches

Great drawing, JB. :)

Originally posted by jbwhite:
Does the ECG??? become another metal path between the two buildings?
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Yes. Even if the EGC's from the house for the lighting are not connecting to the garage premises wiring at all, 250.32 doesn't care. Any metallic path regardless of connections accidental or intentional qualify.

The original poster needs to pull in an EGC for the feeder, sized according to 250.122. :)
 
Re: detached garage and 3 way switches

ok. time to go look at X-10 switches.

addition to my original post:
for those who dont know the term X-10 they are remote control switches. check out the leviton web site.

put a transmitter switch at the house, and a reciever/switch at the garage.

the signal goes over the power lines, but there is no wires going directly from one to the other.

should work well here.

The great part is you dont have to dig a ditch. :p

[ December 01, 2005, 10:17 PM: Message edited by: jbwhite ]
 
Re: detached garage and 3 way switches

OK I think I have found the allowance of this method as long as all the wires are originating from the garage...no need for X-10.

225.30(D) Different Characteristics. Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.
 
Re: detached garage and 3 way switches

BG, I believe you need at most only one more conductor, if the three lighting groups are all on one circuit. I'd suggest using a #12 for less voltage drop, for the distance and the load.

You'd need one hot from the garage to the house to feed all three switches, and then three pairs of travelers back to the garage. This will place the three switch legs and the neutral at the garage.
 
Re: detached garage and 3 way switches

Originally posted by georgestolz:
Even if the EGC's from the house for the lighting are not connecting to the garage premises wiring at all, 250.32 doesn't care. Any metallic path regardless of connections accidental or intentional qualify.

The original poster needs to pull in an EGC for the feeder, sized according to 250.122. :)
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Section 250.32(B)(2) says "there are no continuous metallic paths bonded to the grounding system in both buildings or structures involved"

So its not just any metal path, its ones grounded on both ends. So I agree you need an EGC in the switch circuits going between the buildings. But as long as there are no other circuits in the box at the non-feeding structure, that EGC shouldn't be a problem and the garage feeder can remain as 3-wire.

If you tried to mix this into an existing circuit box at the far end that had a grounding wire in it, then you'd be required to tie the EGC's together and now you'd have a grounded metal path between the buildings which would require a 4th wire in the main garage feeder.
 
Re: detached garage and 3 way switches

Originally posted by suemarkp:
Section 250.32(B)(2) says "there are no continuous metallic paths bonded to the grounding system in both buildings or structures involved"

So its not just any metal path, its ones grounded on both ends.
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My problem with this is, that it is very easy to construct a second path without thinking about it. Incidental contact doesn't qualify as being "bonded" together, but it does conduct electricity. That goes against what 250.32 is trying to accomplish.

Technically, you are correct. :)

If you tried to mix this into an existing circuit box at the far end that had a grounding wire in it, then you'd be required to tie the EGC's together...
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...by what?
 
Re: detached garage and 3 way switches

(2002) 250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any separate equipment grounding conductors associated with those circuit conductors shall be spliced or joined within the box or to the box with devices suitable for the use. Connections depending solely on solder shall not be used. Splices shall be made in accordance with 110.14(B) except that insulation shall not be required. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire (fixture), or other device fed from the box will not interfere with or interrupt the grounding continuity.
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If I'm using nonmetallic boxes, then the EGCs of the second circuit not associated with the first circuit aren't required to touch the EGCs of the first circuit.

If I'm using metallic boxes, then the two unassociated circuits' EGCs are going to be in contact, by virtue of the fact that they are both required to be connected to the same box.

With the exception of...
Exception: The equipment grounding conductor permitted in 250.146(D) shall not be required to be connected to the other equipment grounding conductors or to the box.
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...isolated ground receptacle circuits, which are not required to be in contact with the box.

The purpose of 250.148 is to ensure the "Continuity and Attachment of Equipment Grounding Conductors to Boxes." :)
 
Re: detached garage and 3 way switches

Originally posted by georgestolz:
If I'm using nonmetallic boxes, then the EGCs of the second circuit not associated with the first circuit aren't required to touch the EGCs of the first circuit.
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I can not agree with your interpretation.

(2002) 250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any separate equipment grounding conductors associated with those circuit conductors shall be spliced or joined within the box or to the box with devices suitable for the use. Connections depending solely on solder shall not be used. Splices shall be made in accordance with 110.14(B) except that insulation shall not be required. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire (fixture), or other device fed from the box will not interfere with or interrupt the grounding continuity.
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The only 'out' (other than IGs) is if you have a set of circuit conductors that include a ground that simply pass through the box without a splice or termination.
 
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