proper way to ground an immersion tank heater with EMT/LFMC

E

emiller233

Senior Member
Location
pittsburgh, pa
Occupation
Controls-Automation engineer
What is the proper way to ground an immersion tank heater when using EMT & LFMC for the conduit? EMT until we get near the heater, EMT to LFMC fitting, and then a short piece of LFMC
All fittings are cUL Listed for both conduit types.

The immersion heater MFGR says we must use high-temperature wire for it. So, looking to use something like the wire below and the conduit as the ground.
High-Temperature Stranded Wire, Silicone-Coated Fiberglass Outer Insulation, 14 Gauge
 
emiller233 said:
What is the proper way to ground an immersion tank heater when using EMT & LFMC for the conduit? EMT until we get near the heater, EMT to LFMC fitting, and then a short piece of LFMC
All fittings are cUL Listed for both conduit types.

The immersion heater MFGR says we must use high-temperature wire for it. So, looking to use something like the wire below and the conduit as the ground.
High-Temperature Stranded Wire, Silicone-Coated Fiberglass Outer Insulation, 14 Gauge
Click to expand...
How does it terminate to the heater and what is it being immersed in?

EMT and LFMC fittings are or can be "rain tight" but I wouldn't call either one something that is immersible with the intent of keeping the interior dry. If the heater has potted leads and you are just sleeving them through the LFMC that may be ok but if you have terminations in a splice box of some kind, I think it has great chance of getting whatever liquid is being immersed into the enclosure.
 
kwired said:
How does it terminate to the heater and what is it being immersed in?

EMT and LFMC fittings are or can be "rain tight" but I wouldn't call either one something that is immersible with the intent of keeping the interior dry. If the heater has potted leads and you are just sleeving them through the LFMC that may be ok but if you have terminations in a splice box of some kind, I think it has great chance of getting whatever liquid is being immersed into the enclosure.
Click to expand...
there are just studs inside of the heaters housing on the end of the heating element, including one for a ground on the housing itself. Terminate the wires using crimp-on ring lugs.
It will be immersed in hydraulic oil, not sure of the exact type yet (waiting on the customer).

the conduit itself wont be mounted outdoors, its inside of a room. Theres no splice boxes in the run, whill be a homewurn from the breaker to the heater, roughly a 30' run.
The heaters conduit housing is outside of the tank, and i believe there will even be a dry well installed in the tank for the heater, so they dont have to drain the tank to swap it out. Something along the lines of this one:
1750117122226.png

I don't think we need to run a separate ground, but if we do I'm assuming we use another piece of high-temperature wire and some green tape on the ends?
 
So the entire thing is not immersible, just the main surface of the element is inserted through a threaded hub in the wall of the tank it looks like.

Probably doesn't even need to be liquidtight conduit and certainly doesn't like anything more than NEMA 1 enclosure for the terminations either. LT not prohibited though.
 
kwired said:
So the entire thing is not immersible, just the main surface of the element is inserted through a threaded hub in the wall of the tank it looks like.

Probably doesn't even need to be liquidtight conduit and certainly doesn't like anything more than NEMA 1 enclosure for the terminations either. LT not prohibited though.
Click to expand...
Correct. Do I need a separate ground wire? If the LFMC is under 6 feet?
 
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