Fuses in Class I Division 2 Again...

[gerbonic]

It's been discussed but I want to ask more specifically.

Fuses for short circuit protection for instrumentation are allowed in gp enclosures if

"fuses for overcurrent protection of instrument circuits not subject to overloading in normal use shall be permitted to be mounted in general-purpose enclosures if each such fuse is preceded by a switch complying with 501.105(B)(2)."

Does this mean that I am required to install a disconnect switch in my panel ? Does the circuit breaker in the safe area count?

I have been looking for simple din rail mounted class I d 2 toggle switches and they don't appear to be common. I want to add fuses to instrument wiring but don't know of I can find a decent hazardous area din mounted toggle.

Any suggestions?

 

[don_resqcapt19]

That seems to be more restrictive than the requirement in 501.115(B)(3).

 

[petersonra]

It's been discussed but I want to ask more specifically.

Fuses for short circuit protection for instrumentation are allowed in gp enclosures if

"fuses for overcurrent protection of instrument circuits not subject to overloading in normal use shall be permitted to be mounted in general-purpose enclosures if each such fuse is preceded by a switch complying with 501.105(B)(2)."

Does this mean that I am required to install a disconnect switch in my panel ? Does the circuit breaker in the safe area count?

I have been looking for simple din rail mounted class I d 2 toggle switches and they don't appear to be common. I want to add fuses to instrument wiring but don't know of I can find a decent hazardous area din mounted toggle.

Any suggestions?

why does it need to be din rail mounted? why not get a selector switch and mount it in a box on the subpanel. you probably only need one. you can get a regular selector switch operator and put sealed contacts on it.