Do I have to insulate the safety switch ?

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>I would like to start by saying how much I like your web site. I have worked as a maintenance electrician for a number of years, without any formal training. I have advanced to the position of facility engineer. I have been asked to research the NEC and find an answer to a possible problem. If possible could you provide some insight to following question???

I have a welding shop that was built in the mid 70's. The 480 volt, 3 phase, Delta fusible safety switches were mounted on the utility piping runs. The safety switches are attached to the piping using unistrut and pipe clamps. The piping consists of one air, one natural gas, one oxygen and one welding gas pipe. My question is " do I have to insulate the safety switch from the pipe or can I leave it as is"???

Harold Filer
Fabrication Facility Engineer

Harold, this is not a good method of support. Any electrical installation regardless of any other systems, even if just water, should not be attached to a system for support.

An independant means of support such as unistrut attached to the floor would be better. Look at the NEC and using conduit as a means to support other conduit in article 300, it is basically not allowed. (I don't have my code book at home right now or I would be more specific)

My point is I'm sure there are other codes to consider beyond the NEC in this case.

I don't normally shoot from the hip, but I would suggest a change in any case.

Roger

HAROLD I agree with Roger I think ART 314.23[A] SURFACE MOUNTING would also cover this .Besides the NEC code I think the fire codes might be a problem .As far as my 15 yrs experince I would change it A.S.A.P. you have a dangerous situation there with those gasses . If something should happen to smash into the safty switch and brake those pipes you have [1] fuel [2]oxygen [3] and the source. Something to think about ?

Consider the stress that the pipes will be subjected to when the switch is operated as well, especially in an emergency when someone just yanks the switch down as quickly as possible.

Hi

Mount your switches so that the world could fall down around them and they would still be standing.

Some sort of unistrut rack or angle iron rack should remedy this.