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Old 09-19-2019, 10:25 PM   #1
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Question Circuit breaker for 3HP Well pump

I recently had a 3HP, 230v, Franklin Well Pump installed, and the electrician placed it on a 30amp two pole circuit breaker. But, upon county inspection they stated it couldn't be on a 30amp and of course didn't provide a recommendation. Now I'm stuck for the last two weeks with my electrician stating its fine to be on a 30amp break, the county stating "no", while the Franklin Manual stating that model takes a 40amp breaker. The pump has been running fine for the last 3 weeks on the 30amp break, but I'm concerned the county inspector will insists its changed. Thoughts on how to resolve???
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Old 09-19-2019, 11:13 PM   #2
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Are you certain the manual states a 3hp 230v motor needs to be on a 40A?

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Old 09-19-2019, 11:35 PM   #3
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From the chart that describes the what model of motor the maximum per NEC and Typical Submersible lists 40 as the circuit breaker.
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Old 09-19-2019, 11:56 PM   #4
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What is the model #

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Old 09-20-2019, 12:47 AM   #5
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Here's what the code says about breaker sizing.....

430.6(A)(1) paraphrased a bit but it states that you must use the values given in table 430.248 for a single phase motor, not the nameplate value.

430.52(C)(1) says to use table 430.52 and if the value does not correspond with a standard breaker size, you can go to the next higher standard size.

Table 430.52 states that for a basic breaker you can go up to 250% of the value given in table 430.248. This is the maximum, there is no minimum.

Table 430.248 gives the current of a 3 HP 230 volt single phase motor as 17 amps.

17 X 2.5 = 42.5 Since there are no 42.5 amp breakers, the next standard size is 45. This would be the maximum legal size.

If a 30 will start the motor, it is perfectly code-compliant. So is a 35, 40 or 45 but not a 50.

This doesn't mean the inspector is an idiot........in my experience, about 1 in 10 inspectors actually know how to size a motor breaker according to code. As you can see above, it's not all that easy........
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Old 09-20-2019, 08:14 AM   #6
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I agree 30 amps is fine and the inspector may be reading the max overcurrent protective device. That does not mean it has to be 40 amp. This is for the inspector and your electrician to solve, not you. I would not worry about it.
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Old 09-20-2019, 10:10 AM   #7
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A 40 amp breaker is inexpensive, why not just change it?
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Old 09-20-2019, 07:21 PM   #8
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Most likely the inspector has seen 12g wire on a 30 amp breaker and failed it.
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Old 09-20-2019, 09:18 PM   #9
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Quote:
Originally Posted by gpop View Post
Most likely the inspector has seen 12g wire on a 30 amp breaker and failed it.
I was thinking there was more to this story, yes.

Code rules, as micromind pointed out, are for MAXIMUM size, you can use anything smaller that you think might work. There will be a MINIMUM conductor size, and a MAXIMUM breaker size, so long as the breaker size is correct to protect the conductor.

But I agree on micromind's other point too; you MIGHT have an inspector who has actually BEEN an electrician and knows that, at some point, you may end up with that 30A breaker nuisance tripping on you, like when the utility voltage dips a little more than you have now. The inspector may know that your contractor is not going to change it out at your request, so he is helping you out by being the "bad guy" and trying to force the change for you.

The electrician can argue, and maybe win, but most of us know that this is something that eventually comes back to haunt us. I always found that the best policy was to be unremarkable in an inspector's mind. If you challenge them by going over their head, and ESPECIALLY if you win, they remember that the next time they see you on a job and can nit pick you to death.
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Old 09-21-2019, 04:43 AM   #10
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Originally Posted by JRaef View Post
I was thinking there was more to this story, yes.

There has to be more to the story. I can't see the inspector failing because of the breaker, and not giving a reason why. I don't think I've ever seen a inspector fail something without giving a reason. Not always a direct code cite, but never without a reason.
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Old 09-21-2019, 05:37 AM   #11
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Not your fault the inspector rode the short bus.
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Old 10-01-2019, 06:50 PM   #12
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Quote:
Originally Posted by DocNeu View Post
I recently had a 3HP, 230v, Franklin Well Pump installed, and the electrician placed it on a 30amp two pole circuit breaker. But, upon county inspection they stated it couldn't be on a 30amp and of course didn't provide a recommendation. Now I'm stuck for the last two weeks with my electrician stating its fine to be on a 30amp break, the county stating "no", while the Franklin Manual stating that model takes a 40amp breaker. The pump has been running fine for the last 3 weeks on the 30amp break, but I'm concerned the county inspector will insists its changed. Thoughts on how to resolve???
I use a SD Motor Date Calculator and it says a 35,it is based on the 2014 Nec. Have been using this for years and it has never let me down. Also did well repair in N Ill for years
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Old 10-01-2019, 10:52 PM   #13
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Quote:
Originally Posted by John R View Post
I use a SD Motor Date Calculator and it says a 35,it is based on the 2014 Nec. Have been using this for years and it has never let me down. Also did well repair in N Ill for years
Until the inspector farts and gives him a clue about why its unacceptable it really doesn't matter what the book says. The inspector can play guess a number between 10 and 40 then once he has signed off its probably going to be swapped back to a 30.
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Old 10-02-2019, 07:40 AM   #14
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