Class 1 Division 1 Sewage lift station

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Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Hi.
In a Sewage lift station Class 1 Division 1 Group D ,is it assumed that the Float switches in the tank are to be intrinsic?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Not necessarily. I never did, but I'm not a big IS fan to start with. IS installations are far more complex than most think and are rarely justifiable for a single control circuit. Article 504 is just the beginning, and ANSI/ISA-RP 12.06.01 is OSHA enforceable under the general duty clause.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Thank you.

So basically a can of worms.


Is there a situation where you have no choice but to wire IS?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Dunno. Personally, I've never been in such a situation for a single circuit and I can't imagine where it would ever be an absolute necessity. Occasionally, it is inherently offered in a few small "package" systems and it's OK.

Where IS is the major DCS, it can be pretty cost effective for a medium to large facility. It can also often be justified where the weight of explosionproof equipment in an installation is a consideration, such as offshore drilling rigs which usually have many Class I, Division 1 compartments.
 
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