is this a legal emergency lock-out mechanism?

[malachi constant]

HI all,
I've never seen this before. It appears to be a mechanical device for a manual emergency power transfer system that prevents the utility and generator breakers from being simultaneously closed. We found one instance where the transfer protocol was clearly labeled, but this particular building there was minimal labeling. Is it legal?

 

[LarryFine]

It is. I've used the exact same device several times.

https://www.schneider-electric.us/en/product/QO2DTI/circuit-breaker-mechanical-interlock-qo/

https://www.schneider-electric.us/en/faqs/FA289096/

 

[infinity]

Looks good to me. Not one of those internet brands but from an actual OEM lockout kit.

 

[malachi constant]

Good to know. We will make a mental note of this as a low-cost manual transfer switch solution. Thanks all!

 

[infinity]

Does anyone have a requirement that states that these interlocks have to be listed?

 

[kwired]

you can buy this with breakers, interlock, hold downs all included in the package

https://www.homedepot.com/p/Square-...-Manual-Transfer-Switch-QO48M60DSGP/100096290

Very possibly the one in OP's picture was purchased that way.

Need to supply more than 4 poles for branch circuits? Feed another loadcenter off the unused main lugs of this panel.

 

[Besoeker]

It is. I've used the exact same device several times.

https://www.schneider-electric.us/en/product/QO2DTI/circuit-breaker-mechanical-interlock-qo/

https://www.schneider-electric.us/en/faqs/FA289096/

Isn't it a mechanical interlock between the two supplies rather than a lock off?

 

[iceworm]

Discussion limited to Optional Standby Systems

I agree, they work great and are safe.

Does anyone have a requirement that states that these interlocks have to be listed?

Yes sometimes that is an issue but it should not be.

NEC 702

No mention of transfer switches requiring listing
Recognizes gens less than 15kW may be un-bonded​

NEC 445 Recognizes gens less than 15kW may be un-bonded

NEC 250.34, 250.35

For this type of interlock, the gen is not a Separately Derived System. The house and generator neutrals are solidly connected. One would have to remove the N-G bond in the generator.

It is what I used I my last house.

Well, there is one safety issue. There are inspectors that will burst into flames walking by the installation.

the worm

 

[LarryFine]

Isn't it a mechanical interlock between the two supplies rather than a lock off?

It is, being used as a transfer switch.