Cable on the secondary of an ATS switch protected by breaker on the primary

[mull982]

Can a cable located on the load side of an ATS switch be protected by a breaker on the line side of the ATS? For instance if there was a #6awg cable rated at 65A on the load side of the ATS could this be protected by a 60A breaker at a panel on the line side of the ATS?

What if for this same case the #6 cable had a 100A breaker at the upstream panel on the line side of the ATS however there was a 60A main breaker at a panel on the load side of the ATS that the #6 cable fed into? Would this be a version of the tap rule?

 

[jim dungar]

The ATS is not a 'source' nor is it a protective device, it is not much more than a glorified 3-way. You need to follow the rules in 240.4.

 

[mull982]

The ATS is not a 'source' nor is it a protective device, it is not much more than a glorified 3-way. You need to follow the rules in 240.4.

O.K so with the rules in 240.4 what does this allow for a #6 wire being fed from an upstream 100A breaker but terminating into a 60A breaker at a panel downstream.

Doest this apply to the tap rule? What if the cable run is entirely inside can the tap rule be applied?

 

[rcwilson]

The ATS has two sources. The overcurrent protection on both sources has to protect the downstream load cables.

 

[jim dungar]

Doest this apply to the tap rule? What if the cable run is entirely inside can the tap rule be applied?

There is no single tap rule.

There are provisions in 240.21(B) that may allow the installation you describe.