anything wrong with this TAP

[farmantenna]

Here's what some electricians in my area do. Residential house with Kohler 400 amp service rated transfer switch outside. Instead of installing circuits and conduits for generator battery charger and block heater to one of two indoor panels they install inside the transfer switch enclosure a small fuse block holder and tap anyway they can with #10 or #12 wire. 240.21 seems to allow it. probably shouldn't put small wire under the lugs but.. No inspector has rejected it but I've seen all kinds of violations pass.

 

[CoolWill]

Here's what some electricians in my area do. Residential house with Kohler 400 amp service rated transfer switch outside. Instead of installing circuits and conduits for generator battery charger and block heater to one of two indoor panels they install inside the transfer switch enclosure a small fuse block holder and tap anyway they can with #10 or #12 wire. 240.21 seems to allow it. probably shouldn't put small wire under the lugs but.. No inspector has rejected it but I've seen all kinds of violations pass.

I'm not sure how a #10 would fulfill the requirements of either the 10 ft. or 25 ft. tap rule if the service disconnecting means is 400 amps. Having said that, it's probably fine from a practical standpoint.

 

[wwhitney]

I'm not sure how a #10 would fulfill the requirements of either the 10 ft. or 25 ft. tap rule if the service disconnecting means is 400 amps.

If you read the 10' tap rule 240.21(B)(1), then you'll see that requirement for an ampacity at least 1/10 of the upstream OCPD only arises "For field installations, if the tap conductors leave the enclosure or vault in which the tap is made, . . ."

Cheers, Wayne

 

[tortuga]

I agree with Wayne but what does the connection look like at the start of #10 tap?
Is it tucked under a load side lug of the transfer?
What do the installation instructions say about it?

 

[CoolWill]

If you read the 10' tap rule 240.21(B)(1), then you'll see that requirement for an ampacity at least 1/10 of the upstream OCPD only arises "For field installations, if the tap conductors leave the enclosure or vault in which the tap is made, . . ."

Cheers, Wayne

Well there you go. Seems like a legit setup

 

[don_resqcapt19]

Here's what some electricians in my area do. Residential house with Kohler 400 amp service rated transfer switch outside. Instead of installing circuits and conduits for generator battery charger and block heater to one of two indoor panels they install inside the transfer switch enclosure a small fuse block holder and tap anyway they can with #10 or #12 wire. 240.21 seems to allow it. probably shouldn't put small wire under the lugs but.. No inspector has rejected it but I've seen all kinds of violations pass.

Unlikely that the lug is listed for more than one conductor, so you can't put the tap in with the power conductors.

 

[tortuga]

If I am not mistaken I think other brands like Generac do that from the factory, seems like a bad design for them not to already have that in there.

 

[petersonra]

A lot of lugs for such things have a tapped hole for such connections.

 

[Birken Vogt]

This is my main line of business. Most transfer switches have .250 faston auxiliary terminals, or small threaded holes for a screw and ring termianl, one place or another you can tap for battery charge wiring if you look closely and are creative. I never double lug, there is always a compliant way to do it instead.