only load wires in a conduit

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middlechamber

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Hi,
Besides a code violation..... I came across a standby generator installation where the designated loads run from the existing service panel to the ATS with 16 circuits only had the loads run inside the non metallic conduit, there were no neutrals or even a ground. Please tell me the effects as I am theorizing on my own.
 
Sorry, but I do not understand your description. Are there wires running along the same path as the conduit, but run outside the conduit? What exactly is inside the conduit? Why would there be individual circuit wires going to the ATS? Generally, there would be a panel immediately downstream of the ATS, and all circuits that are intended to receive standby power would be connected to that panel. Can you clarify your situation?

As a side issue, if you have 16 wires in the same conduit, and if they are all current-carrying conductors, then you will have a serious derating requirement. Is that a problem with this installation?
 
middlechamber said:
Hi,
Besides a code violation..... I came across a standby generator installation where the designated loads run from the existing service panel to the ATS with 16 circuits only had the loads run inside the non metallic conduit, there were no neutrals or even a ground. Please tell me the effects as I am theorizing on my own.
Click to expand...

So the emergency circuits are being fed from the generator but the neutrals we left landed at the service?

Was a neutral ran to the ATS?
 
hbiss said:
I don't think the OP is talking about an ATS at all. Most likely something like this- http://www.electricgeneratorsdirect.com/Images/Reliance-Controls-310CRK/i50928.html

If a non metallic conduit was used, yes there would need to be a ground conductor. There should also be a neutral from the generator inlet receptacle to the panel. Can't see how it would work without- unless all loads were 220.

-Hal
Click to expand...
That is my opinion too.
The intended use (which may or may not be Code compatible depending on interpretation) is to run only the hot wires of each branch circuit from the main panel (breaker lug) out to the corresponding branch switch and back again to be wire nutted to the load wire(s).

The neutral remains in place in the original panel and only the first two double switches and their corresponding breakers can be used for either 240 loads or 120/240 MWBCs. it takes some common sense to wire it up correctly, and yes the generator neutral would require one full sized wire to the neutral bus of the original panel and the hots go directly to the circuit transfer panel.
The generator must NOT be wired up as an SDS with its own ground neutral bond.
The current in the raceway to the original panel will balance out to zero when all branches are running off POCO power, as with a switch leg. But when running off the generator the current will be exactly the vector sum of the transferred branch currents and the rule about all of the wires of a circuit running in the same raceway is arguably violated.
Note that each breaker in the transfer panel is only in circuit when its branch has been transferred to generator.
The two voltmeters above the row of switches show generator current for each hot, allowing for manual balancing and load shedding.
 
GoldDigger said:
That is my opinion too.
The intended use (which may or may not be Code compatible depending on interpretation) is to run only the hot wires of each branch circuit from the main panel (breaker lug) out to the corresponding branch switch and back again to be wire nutted to the load wire(s).

The neutral remains in place in the original panel and only the first two double switches and their corresponding breakers can be used for either 240 loads or 120/240 MWBCs. it takes some common sense to wire it up correctly, and yes the generator neutral would require one full sized wire to the neutral bus of the original panel and the hots go directly to the circuit transfer panel.
The generator must NOT be wired up as an SDS with its own ground neutral bond.
The current in the raceway to the original panel will balance out to zero when all branches are running off POCO power, as with a switch leg. But when running off the generator the current will be exactly the vector sum of the transferred branch currents and the rule about all of the wires of a circuit running in the same raceway is arguably violated.
Note that each breaker in the transfer panel is only in circuit when its branch has been transferred to generator.
The two voltmeters above the row of switches show generator current for each hot, allowing for manual balancing and load shedding.
Click to expand...

...than the wires pulled down to a three way light switch would also be a violation if that were true? :happyno:
 
jusme123 said:
...than the wires pulled down to a three way light switch would also be a violation if that were true? :happyno:
Click to expand...

True. But apparently not a practical problem, since the rest of the wires are not traveling in a parallel raceway or something that unusual.
If the only thing in the raceway is the two travelers, there will always be unbalanced current when the light is on. If the common wire from the far end of line switch accompanies the travelers back, then there will be zero current inside the raceway.
Same way an ordinary switch leg from powered fixture to switch is balanced.

How would you feel about a switch leg where the hot wire from the powered fixture box comes into the switch box in one raceway and the other wire goes back to the fixture in a different raceway?
 
Not a violation

Not a violation

I see no violation (or any other problem) except the lack of grounding. The net current through the raceway is zero under all conditions. These are just a special kind of switch leg. The single large neutral carries all the return current when running on generator power, and when it's running on utility power there are just 16 individual switch loops. The transfer switch enclosure needs to be bonded if it's metal, but other than that there's no problem here.
 
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