Optional Standby Generator- control and power sharing raceway

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Flatpad

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I need to do some fancy piping from an ATS to a generator around the base of a house due to odd layout and customer restraints. It would be MUCH more cost effective to only do this with 1 raceway instead of 2. From everything that I've read, I should be perfectly fine running the 120V and 240V control wiring in the same raceway as the power. In total I would have 3 #3's, a #8, and 6 #14's which would fit fine in a 1 1/4" pipe. I could use as small as #18 for the control wiring.


Any code issues that I am missing?
 
Flatpad said:
I need to do some fancy piping from an ATS to a generator around the base of a house due to odd layout and customer restraints. It would be MUCH more cost effective to only do this with 1 raceway instead of 2. From everything that I've read, I should be perfectly fine running the 120V and 240V control wiring in the same raceway as the power. In total I would have 3 #3's, a #8, and 6 #14's which would fit fine in a 1 1/4" pipe. I could use as small as #18 for the control wiring.


Any code issues that I am missing?
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your control wiring is 120/240 vac?
By code no, by mfgrs. instructions, maybe.
You said you've read things so go from there.
 
Judging from what you have wrote so far, this is a Generac unit, in which they do it all the time from the factory. Just keep in mind that all of the wires contained in the conduit must be rated for the highest voltage in there. No thermostat wire for the low voltage controls. Since you planning on using #14 ga. There should be no problem there. Kohler tech have said that they will not sign off on the startup if the control wiring is combined with the higher voltages. But if yours is a Generac, there should be no problem.
 
hillbilly1 said:
Judging from what you have wrote so far, this is a Generac unit, in which they do it all the time from the factory. Just keep in mind that all of the wires contained in the conduit must be rated for the highest voltage in there. No thermostat wire for the low voltage controls. Since you planning on using #14 ga. There should be no problem there. Kohler tech have said that they will not sign off on the startup if the control wiring is combined with the higher voltages. But if yours is a Generac, there should be no problem.
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You got it! It's a Generac. And yes, all the wiring will be 600v THWN.
Thanks!
 
Flatpad said:
When he said "By code no" I believe he was answer my question "any code issues?"

He wasn't saying that it's not allowed by code, he was saying that there are no issues.
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Well you have to watch him, he's sneaky :lol::lol::bye: He thinks things will work if you don't strip the insulation and just put it under the breaker lug :happyno::happyno:
 
ceb58 said:
Well you have to watch him, he's sneaky :lol::lol::bye: He thinks things will work if you don't strip the insulation and just put it under the breaker lug :happyno::happyno:
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Allright now!
you don't have to worry about those pesky faults and such when you don't strip the wire. And for the record that was not me but someone who got a real earfull from me when i tracked them down,,,,, LOL :eek:)
 
Flatpad said:
Yes.

Manufacturer's instructions do not specify either way. On some of their ATS's that are prewired, they run the power and control together.

I'm a afraid I do not understand what you mean :(
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If the manufacturers written instructions do not prohibit you running them in the same raceway then there is no other reason that would stop you.
That would be in the manual and you have read that and it does not. So have at it. :0)
 
I would look at art 725.136(A). In many cases the low voltage must be run separately and in most cases I never see it done that way. It all depends on the class of the trany
 
Dennis Alwon said:
I would look at art 725.136(A). In many cases the low voltage must be run separately and in most cases I never see it done that way. It all depends on the class of the trany
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See 725.130. 725.136(A) would only apply if Class 2 or 3 and using Class 2 or 3 wiring methods. If Class 2 or 3 and using Class 1 wiring methods under 725.130(A), that sends you to 725.46 which essentially says you install per Article 300 Part I, using appropriate wiring methods of Chapter 3.
 
Flatpad said:
You got it! It's a Generac. And yes, all the wiring will be 600v THWN.
Thanks!
Click to expand...

I hate to point this out but if this is a Generac you only have line voltage on N1 and N2.
194/15B is your 12vdc pos.
23 is neg. 12vdc transfer signal
and 0 is 12 neg. (not used on newer models with charger built in the main mother board in the generator)

The fact your using #3's for the generator feeds tells me you have a 17 or 20kw Guardian

Here is the note from a 20kw model wiring diagram:

NOTE: POWER LEADS AND TRANSFER SWITCH LEADS TO BE RUN IN TWO DIFFERENT CONDUITS.

EXCEPTIONS: IF THE INSULATION RATING ON ALL WIRING IS RATED FOR 600V AND THE LENGTH OF THE CONDUIT IS 30ft OR LESS IT IS ACCEPTABLE TO INCLUDE GENERATOR CONTROL & POWER WIRING IN ONE CONDUIT
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These instructions as well as most of the wiring diagrams are very close to being the same for most of the Guardian line from 8kw thru 60kw, the actual wiring numbers I.E. 194/15B can be different on some models as well as using the 0 neg. wire but 23 is in all cases the transfer trigger control wire that tell the transfer switch to transfer to the generator, N1 and N2 are the utility sense to tell the main control board that the utility has failed and each are tied through a 5 amp glass fuse to each leg coming from the utility.

On the smaller all in one transfer panel (100 amp) Generator does supply a prewired whip with both control and power in that same whip but it is under their 30 foot limit as stated above.
 
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hurk27 said:
I hate to point this out but if this is a Generac you only have line voltage on N1 and N2.
194/15B is your 12vdc pos.
23 is neg. 12vdc transfer signal
and 0 is 12 neg. (not used on newer models with charger built in the main mother board in the generator)

The fact your using #3's for the generator feeds tells me you have a 17 or 20kw Guardian

Here is the note from a 20kw model wiring diagram:



These instructions as well as most of the wiring diagrams are very close to being the same for most of the Guardian line from 8kw thru 60kw, the actual wiring numbers I.E. 194/15B can be different on some models as well as using the 0 neg. wire but 23 is in all cases the transfer trigger control wire that tell the transfer switch to transfer to the generator, N1 and N2 are the utility sense to tell the main control board that the utility has failed and each are tied through a 5 amp glass fuse to each leg coming from the utility.

On the smaller all in one transfer panel (100 amp) Generator does supply a prewired whip with both control and power in that same whip but it is under their 30 foot limit as stated above.
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Interesting, on all of the Guardians I have installed over the years (none lately though) the charger has always been out at the generator, either piggy backed with the sense wires, or a separate set of 240 volt wires for the charger, and then the set of 12 Vdc wires to control the transfer switch as you mentioned. The 12 Vdc controls a simple cube relay, nothing electronic, so I don't think there would be sufficient induced voltage to affect the controls on longer runs, so it's kinda odd Generac would limit it to 30'. But then they do some strange stuff to begin with!:lol:
 
hurk27 said:
Here is the note from a 20kw model wiring diagram:

NOTE: POWER LEADS AND TRANSFER SWITCH LEADS TO BE RUN IN TWO DIFFERENT CONDUITS.

EXCEPTIONS: IF THE INSULATION RATING ON ALL WIRING IS RATED FOR 600V AND THE LENGTH OF THE CONDUIT IS 30ft OR LESS IT IS ACCEPTABLE TO INCLUDE GENERATOR CONTROL & POWER WIRING IN ONE CONDUIT
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I have seen this posted on other forums, but I don't believe anyone has cited where exactly it came from. I've installed many 20KW Generacs and have never seen this in any of the documentation that came with the generator/ATS nor in the PDFs available online.

Where did you quote that from and are you sure it applies to the generators sold today?

Thank you.
 
Dr Mantis Toboggan said:
I have seen this posted on other forums, but I don't believe anyone has cited where exactly it came from. I've installed many 20KW Generacs and have never seen this in any of the documentation that came with the generator/ATS nor in the PDFs available online.

Where did you quote that from and are you sure it applies to the generators sold today?

Thank you.
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It is located in all RTS transfer switch installation books that come with the transfer switch, not the installation book for the generator.

MD posted a typical installation book (Even with the newer Nexus control system) that is supplied with all Generac RTS type transfer switchs, the wiring diagram (page 9-11) in this PDF is typical of of all Generac RTS ATS wire ups, the only exception is the change of battery charger system and where it is located, when they used to supply the wall wart type (no plug just the lamp cords coming out of it)
At one time the instruction had us installing them in the generator cabinet at the battery, and supplying it with a circuit from the house panel, later they supplied the terminals and a fuse block to connect them in the transfer switch with a tap to one of the load terminals and neutral, they even included the jumper wires crimp on female spade terminals, screws and male spade terminal to do this, and the charger output hooked to 194/15B + and 0 - this back fed the battery through these terminals, the 0 terminal is also tied to the cabinet of the generator for a negative grounding of the battery, when they came out with the Nexus controller they built a float charger system right on the main mother board in the generator, so no external charger is needed.

There is a 178 and 183 terminals on some Generac generators, in most cases you will not use them, they are for remote switch automatic starting for use with a manual transfer switch

hillbilly1 said:
Interesting, on all of the Guardians I have installed over the years (none lately though) the charger has always been out at the generator, either piggy backed with the sense wires, or a separate set of 240 volt wires for the charger, and then the set of 12 Vdc wires to control the transfer switch as you mentioned. The 12 Vdc controls a simple cube relay, nothing electronic, so I don't think there would be sufficient induced voltage to affect the controls on longer runs, so it's kinda odd Generac would limit it to 30'. But then they do some strange stuff to begin with!:lol:
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The electronics is all in the generator, the main controller board is located in the metal box behind where you land your wires, it will have a cover over it, N1 and N2 are an input to this controller and 23 is a -12vdc output to the transfer switch TR relay (ice cube relay) 194/15 is just the positive from the battery that also runs through the 7.5 amp fuse on the generator switch panel, the battery supplies all the power for the controller and the power up to the TR relay, the TR relay switches the set of solenoids that pull the transfer switch one way or the other, these are DC coils fed through a full wave bridge rectifier from the line voltage (240vac), the power to transfer to generator is derived from E-1 and E-2 which is the hots from the generator, this is to keep the transfer switch from transferring to the generator if it is not running or the breaker on it is tripped or off, the transfer to utility coil is fed through the same bridge rectifier but the limit switches will now have it connected to the N1A and N2A which is the utility side of the transfer switch, again if there is no utility power it will not transfer back.

I would presume that the input to the main controller board could be of a high enough impedance that N1 and N2 could pick up some capacitive coupling and if this happens while generator is running it could trigger the system to think that power is restored and transfer back, this could cause it to start cycling back and forth??? that is about the only thing I could see happening, but if it did it could be bad?
 
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