So, maintenance guys at a student housing apartment complex needed to replace a pool heater and went from gas to electric. They got it mostly worked, then called me to check it so they could get the power company to hook up the new meter they put in for it (b/c it's the only thing running on 3-phase in the whole place). None of it's done right, so I'll have to redo it, but what I don't know is where to find a 105a, 3-phase GFI breaker for the circuit. Does anyone even make such a thing?
Pool Heater Disconnect
- Thread starter WildCelt
- Start date
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
100 and 110 are standard size overcurrent devices.
If 105 is rated amps, this is probably considered a continuous load so minimum conductor ampacity and overcurrent protection is 125% of that, so you would need 131 amp conductor minimum (1/0 copper) and overcurrent device would be next size above that which is 150 amps. That be if it is resistance heater. If it is a heat pump (which makes more sense when it comes to what it will likely cost to run it) you need to see the nameplate MCA and MOCP. If 105 is the MCA then all you need is a 105 amp conductor (2 AWG copper) and use whatever it says for MOCP. Unit that big probably has multiple compressors and possibly VFD drives so it might be anywhere from 125 to 200 for MOCP depending those details.
If 105 is rated amps, this is probably considered a continuous load so minimum conductor ampacity and overcurrent protection is 125% of that, so you would need 131 amp conductor minimum (1/0 copper) and overcurrent device would be next size above that which is 150 amps. That be if it is resistance heater. If it is a heat pump (which makes more sense when it comes to what it will likely cost to run it) you need to see the nameplate MCA and MOCP. If 105 is the MCA then all you need is a 105 amp conductor (2 AWG copper) and use whatever it says for MOCP. Unit that big probably has multiple compressors and possibly VFD drives so it might be anywhere from 125 to 200 for MOCP depending those details.
Actual load is 83.27, so the 125% comes to just under the 105 the nameplate said was the required size for the breaker. I know 100 and 110 are the standard breaker sizes, but given that both the nameplate and installation manual specifically stated it required a 105a breaker (and #2 wire), I thought I'd check. I don't do a lot of 3-phase stuff, so I wasn't sure if there were some different sized breakers for that at the high end. Either way, 105 or 110a, I haven't been able to find a GFCI breaker that big.
- Location
- Illinois
- Occupation
- retired electrician
What requires GFCI protection for resistance type pool heaters?
Unless I'm misreading it, 680.5(B) and (C) requires it for outlets on circuits below 480v. Below 150v, Class A; 150v-480v, SPGFCI
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
680.5 is more of a statement saying "when required in this article..." and not specifying any item that requires GFCI protection. I'm not finding anything directly mentioning GFCI protection for electric pool heaters, though anything supplied via receptacle or within certain distance from the pool may still require GFCI protection regardless what it is.
I did find this that possibly applies to what you have:
Does your electric heater controller possibly have other overcurrent protection within it? Like a couple 50-60 amp circuits integrated within?
Yeah, it's hardwired and in a room off to the side of the pool. So are you saying 680.5 is just to identify what type of GFCI if it's specifically required somewhere else? That makes sense, I suppose. I don't do a whole lot of work with pools; most of my water-related work is on lake docks. Everything that leaves the shore has to be GFCI protected, so I figured all the pool equipment with water going through it would also.
- Location
- Illinois
- Occupation
- retired electrician
Yes, that is the only function of 680.5. The locations and equipment that require protection will say "ground fault protection in accordance with 680.5(B) or (C) as applicable"
I am pretty sure there is a special design for pool water heaters that prevents the pool water from coming into contact with the heating elements eliminating the need for ground fault protection.