Generator Control Wiring Conduit

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iand74

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I've been installing a lot of generators recently. Usually the manual requires separate pipes for the control wires (dc) and the load wires (ac) unless the run is less than 30'.

The other day I installed one and the manual made no reference to the control wiring being in a separate pipe. I ran two pipes because that's what i usually do and i didn't have time to go through each page to make sure i wasn't missing something, but I'm not sure if i needed to.

Has anyone run into this? Has anyone run 1 pipe for everything?
 
Do as they do.. not as they say

Do as they do.. not as they say

Generac generators used to say "must be seperate pipes for control wires" BUT sell pre-wired "kits" with ALL the power and control wires in one flexible conduit. I called Tech Support and could not get a straight answer as to why is is OK for them to use one conduit and I have to run two. Now Guardian uses the 30 FT rule for seperate conduits. I think it has to do with UL listing. I just did a job and ran 50 ft. with both power and control in same conduit. just make sure control wires are rated for 600V. It worked just fine :wink:
 
BLACK4TRUCK said:
Generac generators used to say "must be seperate pipes for control wires" BUT sell pre-wired "kits" with ALL the power and control wires in one flexible conduit. I called Tech Support and could not get a straight answer as to why is is OK for them to use one conduit and I have to run two. Now Guardian uses the 30 FT rule for seperate conduits. I think it has to do with UL listing. I just did a job and ran 50 ft. with both power and control in same conduit. just make sure control wires are rated for 600V. It worked just fine :wink:
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thanks, this one was "pre-wired" to but i had to pull the wires and flex conduit off because they weren't long enough.

did you get it inspected?
 
I think its a good practice to install separate, but I suppose that if your control wires are rated properly and you don't have an issue with the nuimber of conductors/fill then it could be done without a code violation (for an optional standby generator)
 
iand74 said:
I've been installing a lot of generators recently. Usually the manual requires separate pipes for the control wires (dc) and the load wires (ac) unless the run is less than 30'.

The other day I installed one and the manual made no reference to the control wiring being in a separate pipe. I ran two pipes because that's what i usually do and i didn't have time to go through each page to make sure i wasn't missing something, but I'm not sure if i needed to.

Has anyone run into this? Has anyone run 1 pipe for everything?
Click to expand...

Last generator I wired, I tried to separate everything, per the boss, but space was limited. In a common 16X16 pull box, I installed a divider, even though my conductors were all 600V insulation. Coming from the pull box, I ran 4 conduits:

2" for AC generator load conductors
3/4" for AC block heater ckt
3/4" for DC batt charger leads
3/4" for DC controls
 
Volta said:
Are the control wires Class 2 for remote control or just regular power circuitry?
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What Volta is alluding to here is the requirement to separate Class 2 wiring from Power wiring. Class 2 wiring, regardless of the insulation type is not to be installed in the same raceway as power wiring. See the FPN that is located following Section 300.3(C). It refers one to Art 725, where you will see the requirement for separating Class 2 wiring from Power wiring.

You will find the same requirement in 640, 727, 760, 800 and 820.
 
BLACK4TRUCK said:
Yes.. it passed inspection without any problem
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Passing an inspection does not necessarily mean the work is installed to code.


Manufacturers that have the factory made whips have had those whips tested with the equipment as part of the listing. That is why they can sell it like that.

Field wiring of whips is treated differently than the factory made whips, as there is little to no control of what happens in the field for this type of wiring.


One of the reasons for not allowing Class 2 wiring installed in the same raceway as Power conductors is that a fault in the power conductors can be imposed on the Class 2 wiring, possibly traveling back to the Class 2 source and starting a fire.
 
I would say that it's only Class 2 wiring if wired as such. If you wire a circuit with an Art. 300 wiring method and feed it with a Class 2 power supply, is it a Class 2 circuit? I say no.

I do mostly Briggs & Stratton Generators. I put all the wires in one conduit. This includes 4 Generator Feed wires (H,H,N,G) and 4 control wires. The control wires are 2 hots for utility sensing by the generator and 2 LV wires for the LED status light at the interior panel. I use #14 THHN for the "control" wires.

Anyone see a violation? I've never failed an inspection.

Mark
 
busman said:
I would say that it's only Class 2 wiring if wired as such. If you wire a circuit with an Art. 300 wiring method and feed it with a Class 2 power supply, is it a Class 2 circuit? I say no.


Anyone see a violation? I've never failed an inspection.

Mark
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The wiring method does not determine whether or not it is a Class 2 system. As I mentioned, for Class 2 wiring, we do not reference 300.3(C).

A Class 2 system is determined by the source. If the source is Class 2, the circuit is a Class 2 circuit and will be required to follow all of Part III of Article 725.
See 725.41(A) - '05 NEC - for the power source info.
Follow the rest of Part III for other requirements in regards to Class 2 installations.
 
Pierre,

I have to respectfully disagree. The FPN at the beginning of Art 725. says that it provides "alternative requirements" to the requirements of Chapters 1-4.

Please check the FPN under 725.52(A) that says that Class 2 can be reclassified as Class 1 and is therefore no longer a Class 2 circuit. Please also check 725.26 that allows Class 1 conductors in the conduit with the power conductors if the insulation is sufficient and the equipment powered is functionally associated.

I still don't think I have any violation.

Mark
 
busman said:
Pierre,

I have to respectfully disagree. The FPN at the beginning of Art 725. says that it provides "alternative requirements" to the requirements of Chapters 1-4.

Please check the FPN under 725.52(A) that says that Class 2 can be reclassified as Class 1 and is therefore no longer a Class 2 circuit. Please also check 725.26 that allows Class 1 conductors in the conduit with the power conductors if the insulation is sufficient and the equipment powered is functionally associated.

I still don't think I have any violation.

Mark
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That is why I mentioned to read the rest of Part III. Sometimes it is difficult at best to write everything one is thinking of when posting.
Yes you can reclassify your wiring if following all of the requirements put forth in that section.
 
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