NEC Code for Protecting Transfer Switch

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Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
How would you intercept the conductors between the meter and the existing main?
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Again this isnt the way I would do it, it was mentioned by a generator vendor, I am simply going to connect the line side of the ATS for the guy, told him his idea was illegal. Was trying to find the code confirming this diagram in a violation.
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
One more time-this is not a compliant or safe design for the reasons I described and then some.
I completely understand and would never do this design, its extremely dangerous and possibly a felony of some sort, I put some code references I found on post #1 in which I wanted to present to you folks to see if those were the best suited if arguing this to a generator expert, my search started with 445.13 (B)

I appreciate you and everyone's input.
 
I am still not clear on what is being asked. In general, there is no problem hitting a service rated ATS with service conductors. The ATS has a service disconnect built into it. As far as the pesky electrons and the NEC go, its just a typical service disconnected and OCPD.

Now if you are asking specifically about doing this with a meter main, then that involves some modification of the equipment, removing factory installed components and doing some rigging, so s probably not kosher. I
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
I am still not clear on what is being asked. In general, there is no problem hitting a service rated ATS with service conductors.
Can unprotected service conductors feed an ATS , if so how is that acceptable. Being that the utility supply from the load of the meter lugs only travels 6" to the main breaker of the distribution part of the combo meter /distribution panel ( all in one ). The concern is manipulating the service to extend to a distant ATS so it can then be run through a disconnect means Incorporated with a generated source which when either active or not the ATS load voltage of either source goes back to the original service panel to feed the existing distribution branch breakers.

For whatever reason I am having trouble thinking the utility provider is ok with extending their un protected potential to a different piece of equipment in this case the ATS mechanism.

I envision a pull section then a meter section then a main disconnect ... from their I can utilize whatever I want how ever I want, putting any number of controls or disconnecting means I desire based on typical principles of course.

I'm not giving up on this one yet ... granted I can do what I think is incorrect based on manufacturer specs, drawings or hearsay, but I just want to be sure its legal.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
There is no reason a transfer switch can't be the first thing encountered after the meter if it is rated Suitable for Use as Service Equipment (SUSE). That transfer switch becomes the main service disconnect, so it is not on the line side of a service disconnect. Everything downstream of that transfer switch must have its neutral and ground separated. Perhaps that's the issue with a meter main.

Going meter to TS to distribution panel is done all the time. Manual TS or ATS. I did this a (long) while back with a manual transfer switch. It did not have an overcurrent device in it, but that is OK as long as the overcurrent device (main distribution panel with main breaker) is immediately adjacent to it.

I have not worked with meter main panels much. I'm sure there are issues there, and I think that is the key to your question. The issues could vary depending on how the meter main is constructed. But using a separate meter, TS, and main distribution panel are not a problem if the TS is marked SUSE.
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
The issues could vary depending on how the meter main is constructed
Thank you Mark for the input. I figure I'll just come off a distribution block to make the transition from utility to ATS, and generator back to ATS to breaker block, ignoring anything within the metering section period. Thanks to you and everyone for giving me input to compare with.
 
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