Wiring to Test Stand ????

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C3PO

C3PO

Senior Member
Location
Tennessee
Please look at the following pictures. This sealtite goes from a disconnect to a test stand used for testing filters. The stand is on wheels and is rolled back and forth a few feet from time to time. I would like to change the sealtite to a rubber cord, but I am not sure if the NEC permits it in this case. The sealtite gets pulled out of it's fittings everytime the stand is moved. It is fed by 200A 480V 3 phase. In my mind the rubber cord would be safer than exposed THHN. Any comments or ideas??




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Tough question. Cord would seem to be a far better choice than the sealtite and would possibly be permissible under 400.7. It would appear, however, to be one of the areas which requires a plug. Kinda pricey at 200 amps (and heavy).
 
I would look at a Meltric plug and if the disconnect does not have fuses you could even eliminate that as Meltric is listed as a disconnect. As far as the sealtight goes, if it was longer, you used a more flexible wire in it and you used a better connector, maybe even one with a Kellum grip, it would not pull out of the connectors when the equipment is moved.
 
If they won't spend the money, then at the very least chastise them a bit and try and get them to tether the unit to the wall so that it can move, but not pull the S.T. out.
 
They look like EMT compression connectors to me. Could be why they don't work.
 
Hubbell / Kellems makes Sealtight connectors with wire mesh strain relief.
They do make them for 2" conduit. They also make them in straight / 45 / and 90 degree configurations. (I would avoid the 90), but you may want to try a 45 if it helps align the sealtight better for the movement.


Or you could remove the grey metallic sealtight, and replace with non-metallic "Orange-Hose" sealtight. The connectors for that style hold very securely.
 
Why do we have codes ? This setup is a total violation, as far as supports go. Also, the

ST can only have 3' unsupported for flexability, a bad plan to begin with.

Cord with strain relief would at least function.
 
John Valdes said:
They look like EMT compression connectors to me. Could be why they don't work.
Click to expand...
They're Sealtite connectors, but they look like the inner metal ferrules were never screwed in all the way.

I've seen Sealtite split from too much tension before pulling out of connectors I've installed.
 
I think a combination of Don's and Larry's ideas would be best.
Conduit to the ceiling and ST down to the stand.
Use Kellems type connectors and a conductor that is flexible.
Thsi thread http://forums.mikeholt.com/showthread.php?t=107476&highlight=locomotive&page=2 has a lot of info on possible "legal" cable types.
I think as long as you are using "stiff" THHN, you will have problems.
 
The main problem I am having now is the old comment we all know and love to hear "it has been fine for years why should we change it now"


ps: I didn't install this, I was working on something else on that stand and saw it. IMHO it needs to be fixed.
 
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