Disconnect for power or control

[wwhitney]

For the schematic in post #6, isn't the question of whether the red control circuitry qualifies as a disconnect (it doesn't) moot, because the two branch circuit breakers in the upper left qualify if readily accessible?

That assumes the "breakers" in the control panel are supplementary OCPD and not the branch circuit breakers. If they are the branch circuit breakers, then they would need to be readily accesible.

Cheers, Wayne

 

[jim dungar]

Wouldnt the relay have the capability of being locked open if the upstream disconnect has the capability of being locked open?

Can you manually operate a locked switch, without purposely defeating the locking method?
Can you manually close a relay that does not have control power?

As has been mentioned several times, there is no safety standard that considers removing control voltage to be equivalent to removing line/power voltage.

 

[LarryFine]

Forgot about Jims something wrong the mechanism that can happen to manual disconnect the switch contactors jammed. If that was the concern NEC never states that to use manual disconnect

Wouldnt the relay have the capability of being locked open if the upstream disconnect has the capability of being locked open?

You're still ignoring the fact that the 240v supply is still entering the control panel.

The requirement is to be able to disconnect power from the entire system, not just the heating elements.

 

[tom baker]

Code section where it states that or its just Dons opinion?

Don never had an opinion, his answers are based on code.

 

[tom baker]

Since you are so sure the control circuit can be a disconnect, approve the plans. The liability is on you when a worker gets injured.