Individual fusing for internal heater bundles?

[rupej]

Hello all,

I have a 3 phase industrial electric water heater (single-pass design installed on a pipe) that has two bundles of heaters internally. The heater was ordered with no controls, just plain elements in an enclosure. The heater's termination box just has 6 terminals (3 per heater bundle).

I didn't see anything in the NEC that requires overload protection- so I assume the fusing is really just to protect the wire, not the heater themselves? In that case, can I size the fuses for the combined pair of heaters and size the wire accordingly? Or do I need to fuse each heater element individually?


Thanks!

 

[petersonra]

Hello all,

I have a 3 phase industrial electric water heater (single-pass design installed on a pipe) that has two bundles of heaters internally. The heater was ordered with no controls, just plain elements in an enclosure. The heater's termination box just has 6 terminals (3 per heater bundle).

I didn't see anything in the NEC that requires overload protection- so I assume the fusing is really just to protect the wire, not the heater themselves? In that case, can I size the fuses for the combined pair of heaters and size the wire accordingly? Or do I need to fuse each heater element individually?


Thanks!

take a look at 422.11, 422.13, 422.47. is this an "appliance"?

if not it is probably covered in article 425. See 425.22 (B) to start.