In-line 3 phase water heater, GFCI needed?

[NMCB13]

I work for a Aquaculture research facility where they designed a recirculation system for salt water, and they want to heat the water. So they purchased a 3 phase, 240 volt, 18 KW (50 amp) in-line water heater. Does this unit require GFCI protection, and if so, what would be the milliamp trip for the unit be?

 

[GoldDigger]

I work for a Aquaculture research facility where they designed a recirculation system for salt water, and they want to heat the water. So they purchased a 3 phase, 240 volt, 18 KW (50 amp) in-line water heater. Does this unit require GFCI protection, and if so, what would be the milliamp trip for the unit be?

Do you want a code answer or a design answer?

Per code, since this is not a swimming pool or a hot tub, no GFCI would be required. There may be an obscure section related to industrial aquaculture that does say something though. I assume that this will not be cord and plug connected?

Per design, if workers are going to reach into the water frequently and maybe suit up and get in for maintenance, cleaning, or whatever, occasionally, I would feel better using some sort of GF detection. But I do not know what is available in three phase 50A breakers.
I do not think that the personnel protection 6ma threshold is necessary, or that the large heater would even meet that standard. On the other hand capacitive leakage from a three phase heating element could well average out close to zero ma.
The next threshold up would be ~30ma, which gives good life safety protection for casual contact, but might not be low enough for full body immersion where it would be difficult to get out once shocked.
I would certainly want to make sure that metal parts of the plumbing nearest the water heater are bonded, even if I did not have a full equipotential grid around the whole installation.
Salt water does make the whole thing more interesting, IMHO.

I think this will get a good amount of discussion.

 

[NMCB13]

There is a company (well several actually) that offer GFI protection for a 60 amp service, North Shore Safety is one. There are other companies that units for a higher amps and voltages....and so does the cost..... but again what is the cost for a persons life? This is what I face on a daily basis with these Scientist's.

 

[kwired]

I have to agree with Golddigger on the fact that uness you have a swimming pool or hot tub, and possibly add fountains (basically anything covered in 680) NEC wouldn't require GFCI.

There is GFCI requirement in Art 682 - but only requires it for 15 and 20 amp receptacles 125-250 volts single phase, and for outdoor applications or some more detailed instances for non outdoors. Your three phase application exempts NEC requirement for GFCI, could still be good design practice though.