Is there a standard for Enclosure Safety

[Jonusmc]

What standard applies to determine what type of enclosure access is to be used? Whether a disconnect, special key or tool to open the door, or just the standard screwdriver. This is beyond the supply disconnect for the main panel. If i have to add an extra enclosure that has some equipment that is beyond 50v ac/dc, what safety precautions are required and what standard is to be used. Not CE.
Thanks

 

[petersonra]

There is not a NEC standard for such things AFAIK. It's not even required to be in the enclosure it disconnects.

NFPA79 has some requirements for disconnect switches.

UL requires certain features so they can be listed.

 

[pfalcon]

You are referencing NFPA79:2007:6.2.3 Enclosure Interlocking

Basically all the 50V+ doors must be interlocked to the main disconnect.

Components are sold by manufacturers such as Allen-Bradley that will remotely interlock satellite enclosures back to the main disconnect.

NFPA79 does not distinquish what tool is used to bypass the interlock other than requiring a method.

NFPA79 is enforceable only through adoption by your company but provides an acceptable answer to the OSHA general duty clause.

 

[Jonusmc]

Pfalcon - thanks for the info. I did not know where in NFPA79 these rules were.
In reviewing 6.2.3 if indicates panels within or adjacent will be interlockws - when required by 5.3.1.4. If they are not within or adjacent - 6.2.4 comes into play.
What I really need to know is when a disconnect is ruled needed - not just interlocked. It looks like 6.2.4 [2] says it - all live parts are seperately enclosed or guarded - would that also be called "fingersafe" and if so, then only the main panel and its connected or nearby panels need a interlocked disconnect. Does that make sense?
Thanks

 

[pfalcon]

Pfalcon - thanks for the info. I did not know where in NFPA79 these rules were.
In reviewing 6.2.3 if indicates panels within or adjacent will be interlockws - when required by 5.3.1.4. If they are not within or adjacent - 6.2.4 comes into play. What I really need to know is when a disconnect is ruled needed - not just interlocked.

NFPA79:2007:5.3.1.1(1) Each incoming supply
NFPA70:2008:430.102(A) Each motor controller - but see Exceptions (which can be the incoming supply disconnect)
NFPA70:2008:430.102(B) Each motor - but see (1) and (2)

It looks like 6.2.4 [2] says it - all live parts are seperately enclosed or guarded - would that also be called "fingersafe" and if so, then only the main panel and its connected or nearby panels need a interlocked disconnect. Does that make sense?
Thanks

NFPA70:2008:100 Enclosed
NFPA70:2008:100 Guarded
NPFA70:2008:100 Live Parts
Fingersafe refers to covering the exposed parts of a component but not preventing contact with a component. Therefore fingersafe will not provide protection meeting 6.2.4(2) requirements.

You should read all of NFPA79:2008:5.3 but see especially 5.3.1.3 and 5.3.1.4