Fuses for Instrument Circuits in Class I Div 2

[ewood8806]

I would like to fuse circuits located in a general purpose junction box in a Class I Div 2 environment. My question is in regards to 501.105(B)(5) where it basically states that fuses are allowed in general-purpose enclosures as long as they are preceeded by a switch complying with 501.105(B)(1).

Does having a switch meeting 501.105(B)(1) apply even if the switch is located in an unclassified area? It seems pointless to have a immersed, Div 2, etc. switch in an unclassified area.

 

[LEO2854]

I would like to fuse circuits located in a general purpose junction box in a Class I Div 2 environment. My question is in regards to 501.105(B)(5) where it basically states that fuses are allowed in general-purpose enclosures as long as they are preceeded by a switch complying with 501.105(B)(1).

Does having a switch meeting 501.105(B)(1) apply even if the switch is located in an unclassified area? It seems pointless to have a immersed, Div 2, etc. switch in an unclassified area.

No it does not.

Welcome to the forum....:thumbsup:

 

[GoldDigger]

No it does not.

Although as a design principle, I would be happier if the switch were within sight of the fuse box and/or the location of the switch were listed on the box.

 

[ewood8806]

Although as a design principle, I would be happier if the switch were within sight of the fuse box and/or the location of the switch were listed on the box.

Thanks alot! In my case, 120V AC is being sent from a mini circuit breaker located in the I/O room (pressurized) for valve proximity status. And actually there are several 120V sources in the enclosure so it may be even messier to put XP switches near the JB.

 

[rbalex]

Sorry for being late to the dance, but there are several explosionproof or Zone rated flameproof (Type "AEx d") compact selector switches available that are suitable under Section 501.105 as disconnects for fuses. This application of Zone rated equipment is suitable under Section 501.2.

 

[petersonra]

Just curious why one would install fuses in a classified area in the first place? It just seems like there is no real benefit to putting them there. I know a lot of people seem to have an unlimited budget for fuses for I/O modules. It just never made sense to me. Lots of extra connections and devices that can fail.