Tank heating -Article 427.22

[Davebones]

We have Anodizing area where we dip and treat different metals .Some of the tank heaters ( 240 volt ) are on indivual GFCI's while we have some ( 480 volt ) which are not GFCI circuit protected .My understanding of 427.22 is that all imersion heaters need GFCI or GFEP protection . Since our main switchgear is GFI protected ( 4000 amp main servive ) would that satisify the requirements of 427.22 or do we need seperate protection for the heaters not on indivual GFI's ?????????

 

[augie47]

I don't see where the NEC is extremely helpful here since it provides no limits. Based on manufacturer specs, the heaters I have seen require 30ma GFP protection. The breaker GF protection is probably more in the 100 amp range. In addition, even it did provide the protection needed, I doubt you would want the "main" to trip if you had heater leakage.