1.5 HP 230v well breaker size?

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Roger9

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Alright guys I’m back with some bs! what would a 1.5HP 230v well be fused to? The well company doesn’t know and they don’t have the specs for it. Im reading online 2 pole 30amp. We just started doing a lot of custom work for a builder who mainly builds in remote areas that require well pumps. I’m not too familiar with what they require.
 
Assuming single phase 240V, a 1-1/2HP single phase motor is 10A in the NEC chart, so the breaker can be UP TO 250%, so 25A max. Wire would need to be rated 12.5A minimum, so 14ga is fine, so long as the motor has thermal protection. If not, and you are using only the breaker, then the breaker must be smaller (15A) but runs the risk of nuisance tripping on start-up.
 
Jraef said:
Assuming single phase 240V, a 1-1/2HP single phase motor is 10A in the NEC chart, so the breaker can be UP TO 250%, so 25A max. Wire would need to be rated 12.5A minimum, so 14ga is fine, so long as the motor has thermal protection. If not, and you are using only the breaker, then the breaker must be smaller (15A) but runs the risk of nuisance tripping on start-up.
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Thank you for this! What a chart in the NEC you’re referring to?
 
Roger9 said:
Thank you for this! What a chart in the NEC you’re referring to?
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Table 430.248 for the motor FLC values, and table 430.52 for the circuit breaker sizes. Then Section 430.32 is what covers Overload Protection. A lot of well motors will have "integral" thermal protection, meaning it is built-into the motor, which is covered under 430.A.2, but you need to know for sure if that is the case. If not then you must have an external "overload relay", which might be part of a well pump protection box (if any), and if there is NOTHING, then you CAN in theory use the breaker, but that gets really tricky. The breaker would need to fall into the limits of 430.A.1 or A.1.C, which will generally mean the breaker has to be within 115% of the motor FLA, or 130%, depending on circumstances. If we assume the motor FLA is 10A, then a 15A breaker only works based on an "next size up" ruling, but as I said, likely will run afoul of nuisance tripping on start-up.
 
Jraef said:
Table 430.248 for the motor FLC values, and table 430.52 for the circuit breaker sizes. Then Section 430.32 is what covers Overload Protection. A lot of well motors will have "integral" thermal protection, meaning it is built-into the motor, which is covered under 430.A.2,
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I think you mean 430.32(A)(2)
Jraef said:
if there is NOTHING, then you CAN in theory use the breaker, but that gets really tricky. The breaker would need to fall into the limits of 430.A.1 or A.1.C, which will generally mean the breaker has to be within 115% of the motor FLA, or 130%, depending on circumstances.
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I think you mean 430.32(A)(1) and 430.32(C)
 
Every submersible well pump I have ever worked on goes like this there is a little 'pumptec' control box:
1716343714828.png

Then the well guy has one of two twisted cables typically THW (non direct bury has to be in conduit to the well head) or the more expensive cable that is UF single conductors twisted together both look like this:
1716344186515.png

Breakers are usually a 2 pole 20 & 12 or 10 AWG wire. Sometimes you see #8 on a deep well.
3rd yellow wire that goes to the pump to start it.
The older pump boxes do not all have overloads, I would look at the installation instructions that come with the "pumptec".
I dont think I have ever seen one on a 30A breaker.
There is also a sticker on the side of the pump controller with nameplate info.
The new ones usually need to run in a special mode the first time to calibrate the overload. Often times 'well guys' try to help and run the wire for me then I have to re do it.
Submersible water pumps have a lot of regional variation so may be different in your area.
 
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