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Old 06-25-2011, 01:39 PM   #1
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Running pool electric


Good afternoon all,

I recently installed a pool (18' above ground aluminum) with a 1.5 HP pump and need to run electric out to it. The run will be fairly short at about 50 feet. There is currently one existing conveince outlet near the pool.

My question is, can I run romex 12-3 across the attic and drop the thhn/thwn down the side of the house? My only other option that I am trying to steer clear of is ripping out a ton of mortared flagstone and concrete pad in order to bury it in conduit.

I am having an electrician do all the work, so the only work I will be doing is the trench and concrete busting if that is my only option.

Thanks for any input in advance!

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Old 06-25-2011, 03:58 PM   #2
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Running pool electric


yes, providing there is not a light in the pool

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Old 06-25-2011, 06:00 PM   #3
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Running pool electric


Do not know your circuiting plan but I personally would not wire a 1.5 HP pump at 120 volts.
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Old 06-26-2011, 10:35 AM   #4
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Let the electrician worry about everything except the trench and concrete busting. This is serious business and if you really plan to hire an electrician he will know what to do make it safe.
My gut feeling is there is no electrician involved and you are trying to do this yourself. I hope you have plenty life insurance on anyone that will use the pool.
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Old 06-26-2011, 11:30 AM   #5
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Quote:
Originally Posted by alten78 View Post
Good afternoon all,

I recently installed a pool (18' above ground aluminum) with a 1.5 HP pump and need to run electric out to it. The run will be fairly short at about 50 feet. There is currently one existing conveince outlet near the pool.

My question is, can I run romex 12-3 across the attic and drop the thhn/thwn down the side of the house? My only other option that I am trying to steer clear of is ripping out a ton of mortared flagstone and concrete pad in order to bury it in conduit.

I am having an electrician do all the work, so the only work I will be doing is the trench and concrete busting if that is my only option.

Thanks for any input in advance!
1 1/2 HP motor @ 120V draws 20 amps. #12 wire with a 50A breaker is needed.

1 1/2 HP motor @ 240V draws 10 amps. #14 wire with a 25A breaker is needed.

At a distance of 50' I recommend #12. The motor should be dual voltage. Connect it @ 220V. Use a 25A 2 pole breaker. The breaker does not have to be GFI. The motor will have to be hard wired. You will not be able to use the 20R twist lock receptacle. If there is a pool light, the pool light has to be in conduit all the way back to the panel.
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Last edited by electures; 06-26-2011 at 02:22 PM. Reason: Corrected breaker size for 240V.
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Old 06-26-2011, 11:35 AM   #6
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[quote=electures;674347]1 1/2 HP motor @ 120V draws 20 amps. #12 wire with a 50A breaker is needed.

1 1/2 HP motor @ 240V draws 10 amps. #14 wire with a 30A breaker is needed.

At a distance of 50' I recommend #12. The motor should be dual voltage. Connect it @ 220V. Use a 30A 2 pole breaker. The breaker does not have to be GFI. The motor will have to be hard wired. You will not be able to use the 20R twist lock receptacle. If there is a pool light, the pool light has to be in conduit all the way back to the panel.[/quot
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Old 06-26-2011, 11:37 AM   #7
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Running pool electric


Personally, I would not install a non-GFCI circuit for a pool.

By looking at NEC 430.6(A)(1) Exception No. 3 I disagree with your motor calculations.

Last edited by brric; 06-26-2011 at 11:57 AM.
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Old 06-26-2011, 02:20 PM   #8
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Originally Posted by brric View Post
Personally, I would not install a non-GFCI circuit for a pool.

By looking at NEC 430.6(A)(1) Exception No. 3 I disagree with your motor calculations.
Here is 430.6(A)(1) and other applicable sections based on a 1.5 HP, 230V motor;

430.6(A) 1 states;
(1) Table Values. Other than for motors built for low speeds (less than 1200 RPM) or high torques, and for multispeed motors, the values given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250 shall be used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, instead of the actual current rating marked on the motor nameplate. Where a motor is marked in amperes, but not horsepower, the horsepower rating shall be assumed to be that corresponding to the value given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250, interpolated if necessary. Motors built for low speeds (less than 1200 RPM) or high torques may have higher full-load currents, and multispeed motors will have full-load current varying with speed, in which case the nameplate current ratings shall be used.

Table 430.248 indicates 10 amps for a 230V 1.5 HP single phase motor.

430.22(A) General states;

(A) General. Conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125 percent of the motorís full-load current rating as determined by 430.6(A)(1).

10A x 125% = 12.5A

Table 310.16 indicates #14AWG is rate for 20A.

Now before you get your panties in a bunch the asterisk refers us to the bottom of Table 310.16 where it states: See 240.4(D).

240.4(D) states;

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

240.4(E) refers to tap conductors which is not applicable here. However, 240.4(G) is a table and tells us that Article 430 applies for motor branch circuit conductors. This means that #14 AWG is specifically permitted to be used for conductors supplying this motor load.

Next we look at sizing the ground fault, short circuit, overcurrent protective device.

430.52 states;

430.52 Rating or Setting for Individual Motor Circuit.
(A) General. The motor branch-circuit short-circuit and ground-fault protective device shall comply with 430.52(B) and either 430.52(C) or (D), as applicable.

(C) Rating or Setting.
(1) In Accordance with Table 430.52. A protective device that has a rating or setting not exceeding the value calculated according to the values given in Table 430.52 shall be used. (Also read the exception.)

Table 430.52 states that for an inverse time circuit breaker (ITCB) protecting a single phase motor it is to be sized at 250% of the FLA as stated in Table 430.248.

10A x 250% = 25A

Based on the above calculation a 25A ITCB is correct.

If the motor fails to start and run then 430.52(C) (1) Exception No. 2(c) can be applied which states;

(c) The rating of an inverse time circuit breaker shall be permitted to be increased but shall in no case exceed 400 percent for full-load currents of 100 amperes or less or 300 percent for full-load currents greater than 100 amperes.

10A x 400% = 40A

Since we canít exceed 400% of the motor FLA we have a 40A ITCB on a piece of #14 AWG conductor.
The real kicker is that if this was a pool filter motor it is code compliant.
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If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
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Old 06-26-2011, 02:28 PM   #9
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Quote:
Originally Posted by brric View Post
Personally, I would not install a non-GFCI circuit for a pool.

By looking at NEC 430.6(A)(1) Exception No. 3 I disagree with your motor calculations.
Here is the calculation for a 1.5 HP, 120V motor;

Motors
430.6(A) 1 states;
(1) Table Values. Other than for motors built for low speeds (less than 1200 RPM) or high torques, and for multispeed motors, the values given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250 shall be used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, instead of the actual current rating marked on the motor nameplate. Where a motor is marked in amperes, but not horsepower, the horsepower rating shall be assumed to be that corresponding to the value given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250, interpolated if necessary. Motors built for low speeds (less than 1200 RPM) or high torques may have higher full-load currents, and multispeed motors will have full-load current varying with speed, in which case the nameplate current ratings shall be used.

Table 430.248 indicates 20 amps for a 120V 1.5 HP single phase motor.

430.22(A) General states;

(A) General. Conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125 percent of the motorís full-load current rating as determined by 430.6(A)(1).

20A x 125% = 25A

Table 310.16 indicates #12AWG is rate for 25A.

Now before you get your panties in a bunch the asterisk refers us to the bottom of Table 310.16 where it states: See 240.4(D).

240.4(D) states;

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

240.4(E) refers to tap conductors which is not applicable here. However, 240.4(G) is a table and tells us that Article 430 applies for motor branch circuit conductors. This means that #12 AWG is specifically permitted to be used for conductors supplying this motor load.

Next we look at sizing the ground fault, short circuit, overcurrent protective device.

430.52 states;

430.52 Rating or Setting for Individual Motor Circuit.
(A) General. The motor branch-circuit short-circuit and ground-fault protective device shall comply with 430.52(B) and either 430.52(C) or (D), as applicable.

(C) Rating or Setting.
(1) In Accordance with Table 430.52. A protective device that has a rating or setting not exceeding the value calculated according to the values given in Table 430.52 shall be used. (Also read the exception.)

Table 430.52 states that for an inverse time circuit breaker (ITCB) protecting a single phase motor it is to be sized at 250% of the FLA as stated in Table 430.248.

20A x 250% = 50A

Based on the above calculation a 50A ITCB is correct.

If the motor fails to start and run then 430.52(C) (1) Exception No. 2(c) can be applied which states;

(c) The rating of an inverse time circuit breaker shall be permitted to be increased but shall in no case exceed 400 percent for full-load currents of 100 amperes or less or 300 percent for full-load currents greater than 100 amperes.

20A x 400% = 80A

Since we canít exceed 400% of the motor FLA we have a 80A ITCB on a piece of #12 AWG conductor.
The real kicker is that if this was a pool filter motor it is code compliant.
__________________
All responses based on the 2011 NEC.
If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
Sizing motors here. Online motor calculator here. Online calculators here.
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Old 06-26-2011, 02:46 PM   #10
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Quote:
Originally Posted by J. V. View Post
Let the electrician worry about everything except the trench and concrete busting. This is serious business and if you really plan to hire an electrician he will know what to do make it safe.
My gut feeling is there is no electrician involved and you are trying to do this yourself. I hope you have plenty life insurance on anyone that will use the pool.
The reason for posting is so i don't have to worry that it is being done wrong and everyone IS safe, ive read on several other threads that not all electricians are pool and pump savvy.

I appreciate your concern, being the network engineer that i am, if its not commucation lines, I don't know it. I'll be the first to admit that I know very little about power and wouldnt take on a project like this on my own, but I do want it done right and especially for personal knowledge.

After reading the posts, im already questioning why he isn't installing 240v...which is exactly why I created this thread, to know what is right and what is wrong.

Thank you all, I will be reading and re-reading

Last edited by alten78; 06-26-2011 at 03:04 PM. Reason: add
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Old 06-26-2011, 02:50 PM   #11
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Quote:
Originally Posted by alten78 View Post
I appreciate your concern, being the network engineer that i am, if its not commucation lines, I don't know it. I'll be the first to admit that I know very little about power and wouldnt take on a project like this on my own, but I do want it done right and especially for personal knowledge.

After reading the posts, im already questioning why he isn't installing 240v...which is exactly why I created this thread, to know what is right and what is wrong.

Thank you all, I will be reading and re-reading
The higher voltage will allow for a smaller breaker.
__________________
All responses based on the 2011 NEC.
If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
Sizing motors here. Online motor calculator here. Online calculators here.
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Old 06-26-2011, 02:58 PM   #12
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Quote:
Originally Posted by electures View Post
Here is 430.6(A)(1) and other applicable sections based on a 1.5 HP, 230V motor;

430.6(A) 1 states;
(1) Table Values. Other than for motors built for low speeds (less than 1200 RPM) or high torques, and for multispeed motors, the values given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250 shall be used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, instead of the actual current rating marked on the motor nameplate. Where a motor is marked in amperes, but not horsepower, the horsepower rating shall be assumed to be that corresponding to the value given in Table 430.247, Table 430.248, Table 430.249, and Table 430.250, interpolated if necessary. Motors built for low speeds (less than 1200 RPM) or high torques may have higher full-load currents, and multispeed motors will have full-load current varying with speed, in which case the nameplate current ratings shall be used.

Table 430.248 indicates 10 amps for a 230V 1.5 HP single phase motor.

430.22(A) General states;

(A) General. Conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125 percent of the motorís full-load current rating as determined by 430.6(A)(1).

10A x 125% = 12.5A

Table 310.16 indicates #14AWG is rate for 20A.

Now before you get your panties in a bunch the asterisk refers us to the bottom of Table 310.16 where it states: See 240.4(D).

240.4(D) states;

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

240.4(E) refers to tap conductors which is not applicable here. However, 240.4(G) is a table and tells us that Article 430 applies for motor branch circuit conductors. This means that #14 AWG is specifically permitted to be used for conductors supplying this motor load.

Next we look at sizing the ground fault, short circuit, overcurrent protective device.

430.52 states;

430.52 Rating or Setting for Individual Motor Circuit.
(A) General. The motor branch-circuit short-circuit and ground-fault protective device shall comply with 430.52(B) and either 430.52(C) or (D), as applicable.

(C) Rating or Setting.
(1) In Accordance with Table 430.52. A protective device that has a rating or setting not exceeding the value calculated according to the values given in Table 430.52 shall be used. (Also read the exception.)

Table 430.52 states that for an inverse time circuit breaker (ITCB) protecting a single phase motor it is to be sized at 250% of the FLA as stated in Table 430.248.

10A x 250% = 25A

Based on the above calculation a 25A ITCB is correct.

If the motor fails to start and run then 430.52(C) (1) Exception No. 2(c) can be applied which states;

(c) The rating of an inverse time circuit breaker shall be permitted to be increased but shall in no case exceed 400 percent for full-load currents of 100 amperes or less or 300 percent for full-load currents greater than 100 amperes.

10A x 400% = 40A

Since we canít exceed 400% of the motor FLA we have a 40A ITCB on a piece of #14 AWG conductor.
The real kicker is that if this was a pool filter motor it is code compliant.
You are ignoring the exceptions.
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Old 06-26-2011, 03:00 PM   #13
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Quote:
Originally Posted by brric View Post
You are ignoring the exceptions.
Which?
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Old 06-26-2011, 05:36 PM   #14
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Quote:
Originally Posted by alten78 View Post
The reason for posting is so i don't have to worry that it is being done wrong and everyone IS safe, ive read on several other threads that not all electricians are pool and pump savvy.
So then find one who is!

You coming onto an internet forum will not give you more knowledge than a professional you are going to hire. If you have that little trust in a tradesman then find a better one.
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Old 06-26-2011, 06:06 PM   #15
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Originally Posted by Speedy Petey View Post
So then find one who is!

You coming onto an internet forum will not give you more knowledge than a professional you are going to hire. If you have that little trust in a tradesman then find a better one.
Thanks and exactly my point!

What used to be a question to help expedite the time to get the job done (whether or not for me to deal with and get an early jump on the trench/concrete busting) has manifested into a discussion where I am now questioning said work.

So to your point, am i coming here looking for more knowledge? No, but i received enough to be a smart consumer and rather be safe than sorry.

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