Intrinsically Safe Areas

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cdcabrera

Member
Location
Riverside, CA
Got a new installation for hydrogen service and the customer wants it to be IS. Skid mounted oil separation unit, all device wiring will be pulled a JB on the edge of the skid. Customer is responsible for wiring back to the control system.

Based on my research I understand the following items
- any wiring method is acceptable
- wiring needs to be blue in color
- cabling/cable trays need to be clearly/permanently identified "Intrinsically Safe" at min every 7.5m or 25ft
- in the event there is wiring that is not IS, it needs to be separate from the IS by 2" min

Anything else I should be considering?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
...
Anything else I should be considering?
A few things:
  • While "standard" wiring methods are generally acceptable there are still special sealing [Section 504.70] and grounding/bonding [Section 504.50] requirements.
  • There must be a Control Drawing [Sections 100, Part I, (definition) and 504.10(A)]. This is a very BIG deal and easy to overlook.
  • "Blue" wiring for identification is permitted but, if used, it must specifically be light blue. [Section 504.80(C)]
 
Location
Ohio
Occupation
Engineer
Another item to remember is that standard wiring methods are acceptable but you still have the same sealing requirements to grapple with when transitioning that wiring from a Hazardous to non Hazardous area. I've heard, but I have not read, the 2020 code cycle made this even more difficult, in tune with the times.
 
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