water heater
- Thread starter howlev
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bphgravity
Senior Member
- Location
- Florida
Re: water heater
The overcurrent protection for a water heater shall not exceed 150% of the nameplate rating, so this would allow a 30-ampere OCD. The conductors would have to be 30-ampere rated as well.
The minimum circuit ampacity is at 125%. #12 us not good for 23-amperes as stated in your post. You would have to go to a #10. It could be protected by a 25-ampere OCD if you desired.
The overcurrent protection for a water heater shall not exceed 150% of the nameplate rating, so this would allow a 30-ampere OCD. The conductors would have to be 30-ampere rated as well.
The minimum circuit ampacity is at 125%. #12 us not good for 23-amperes as stated in your post. You would have to go to a #10. It could be protected by a 25-ampere OCD if you desired.
bphgravity
Senior Member
- Location
- Florida
Re: water heater
Check out Section 240.4(D)
Check out Section 240.4(D)
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: water heater
I'm not 100% sure on my application here, so help me out. 240.4(D) gives the requirments for small conductors, unless modified by (E)through(G). (G) has provisions for motor operated appliances, but not non-motor operated appliances, and therefore a #12 could not be protected by more than a 20A OCPD, because it is not a motor operated appliance.
I'm not 100% sure on my application here, so help me out. 240.4(D) gives the requirments for small conductors, unless modified by (E)through(G). (G) has provisions for motor operated appliances, but not non-motor operated appliances, and therefore a #12 could not be protected by more than a 20A OCPD, because it is not a motor operated appliance.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: water heater
D*mn you Bryan!!!!
J/K
D*mn you Bryan!!!!
J/K
- Location
- Massachusetts
Re: water heater
You can not use a 20 amp breaker for this water heater.
240.4(D) requires the use of 10 AWG for this application when the OCP is greater than 20 amps.
Bottom line for a 240 volt 4500 watt water heater, 25 or 30 amp breaker and 10 AWG minimum.
You can not use a 20 amp breaker for this water heater.
You must use a breaker rated 23.44 amps or above.
240.4(D) requires the use of 10 AWG for this application when the OCP is greater than 20 amps.
Bottom line for a 240 volt 4500 watt water heater, 25 or 30 amp breaker and 10 AWG minimum.
- Location
- Massachusetts
Re: water heater
I am not following you here.
422.13 requires the branch circuit to be 125% of the water heater load, in this case you have said that is 23.44 amps.
210.3 requires us to rate the branch circuit by the size of the overcurrent protection.
The only way to provide a branch circuit that has a rating of 23.44 amps is use overcurrent protection equal or higher than that.
This means a 20 amp breaker is a violation.
You will have to choose a 25 amp or 30 amp overcurrent protection.
With a 25 or 30 amp OCPD 240.4(D) prohibits the use of 12 AWG for this type of application.
Bob
I am not following you here.
422.13 requires the branch circuit to be 125% of the water heater load, in this case you have said that is 23.44 amps.
210.3 requires us to rate the branch circuit by the size of the overcurrent protection.
The only way to provide a branch circuit that has a rating of 23.44 amps is use overcurrent protection equal or higher than that.
This means a 20 amp breaker is a violation.
You will have to choose a 25 amp or 30 amp overcurrent protection.
With a 25 or 30 amp OCPD 240.4(D) prohibits the use of 12 AWG for this type of application.
Bob
- Location
- Massachusetts
Re: water heater
This one?
This one?
I still am not following you.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: water heater
Holwev: Read Bob's post one more time, I think he is right on. The branch circuit must be sized at 125%. The rating of the breaker is what determines the rating of the circuit. For example, you could have 500Kcmil on a 20 amp breaker...you still have a 20 amp branch circuit, not a 380 amp branch circuit.
The section you cite requires the branch circuit to be sized 125% of the nameplate, which is greater than 20 amps after the 1.25 multiplier. You can use any size of wire you want that will carry 23 amps, as long as you don't violate 240.4.
Holwev: Read Bob's post one more time, I think he is right on. The branch circuit must be sized at 125%. The rating of the breaker is what determines the rating of the circuit. For example, you could have 500Kcmil on a 20 amp breaker...you still have a 20 amp branch circuit, not a 380 amp branch circuit.
The section you cite requires the branch circuit to be sized 125% of the nameplate, which is greater than 20 amps after the 1.25 multiplier. You can use any size of wire you want that will carry 23 amps, as long as you don't violate 240.4.
Re: water heater
The definition of branch circuit is the conductors not overcurrent and conductors the conductors must be sized at 125% the overcurrent can not exceed 150% the appliance rated current which is 18.75A. as per art. 422.11 E 3, not the 23+ amps for the wire size as per art. 422.13. Also art. 210.3 is for other then individual branch circuits as this is an individual branch circuit this article does not apply
The definition of branch circuit is the conductors not overcurrent and conductors the conductors must be sized at 125% the overcurrent can not exceed 150% the appliance rated current which is 18.75A. as per art. 422.11 E 3, not the 23+ amps for the wire size as per art. 422.13. Also art. 210.3 is for other then individual branch circuits as this is an individual branch circuit this article does not apply
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: water heater
For example...you have a light pole circuit that is 500' in length. You pull number 4 to allow for voltage drop, and you put it on a 20 amp breaker. You have a 20 amp branch circuit...not an 85 amp branch circuit.
Read 210.3 again. It does not apply only to "other than indidual branch circuits", it simply makes one statement about them. If it applied only to other than individual branch circuits, it would read like this:
210.3 Multi-outlet circuits. This section is... blah blah blah blah blah.
This requires that the branch circuit (not just the conductors...the BRANCH CIRCUIT) be sized at 125%. The rating of a branch circuit is determined by the size of the overcurrent device, not the conductors.
For example...you have a light pole circuit that is 500' in length. You pull number 4 to allow for voltage drop, and you put it on a 20 amp breaker. You have a 20 amp branch circuit...not an 85 amp branch circuit.
Read 210.3 again. It does not apply only to "other than indidual branch circuits", it simply makes one statement about them. If it applied only to other than individual branch circuits, it would read like this:
210.3 Multi-outlet circuits. This section is... blah blah blah blah blah.
Re: water heater
Branch Circuit. "The circuit conductors" between the final overcurrent device protecting the circuit and the outlet(s).
THE CIRCUIT CONDUCTORS FROM THE LUGS OF THE OVERCURRENT DEVICE TO THE OUTLET BRANCH CIRCUIT DOES NOT INCLUDE THE OVERCURRENT DEVICE OR THE OUTLET IN THIS CASE THE WATER HEATER
yOU MAY ALSO WANT TO LOOK AT ART 210.2 AS AN APPLIANCE BRANCH CIRCUIT IS NOT RECOGNIZED IN THIS ART. AS STATED IN ART.210.3 BUT IS RECOGNIZED IN 422
Branch Circuit. "The circuit conductors" between the final overcurrent device protecting the circuit and the outlet(s).
THE CIRCUIT CONDUCTORS FROM THE LUGS OF THE OVERCURRENT DEVICE TO THE OUTLET BRANCH CIRCUIT DOES NOT INCLUDE THE OVERCURRENT DEVICE OR THE OUTLET IN THIS CASE THE WATER HEATER
yOU MAY ALSO WANT TO LOOK AT ART 210.2 AS AN APPLIANCE BRANCH CIRCUIT IS NOT RECOGNIZED IN THIS ART. AS STATED IN ART.210.3 BUT IS RECOGNIZED IN 422
- Location
- Illinois
- Occupation
- retired electrician
Re: water heater
howlev,
First please lose the caps. Thanks.
422.13 requires that the branch circuit rating be at least 125% of the water heater nameplate rating. 210.2 says that Article 210 applies. 210.3 says that the rating of the branch circuit is equal to the size of the branch circuit OCPD. In this case the minimum size branch circuit rating that is permitted is 23.44 amps. That size OCPD does not exist, so the minimum rating of the OCPD is 25 amps. The maximum permitted OCPD for #12 is 20 amps in this case, so this circuit requires #10 wire and a 25 amp OCPD.
Don
howlev,
First please lose the caps. Thanks.
422.13 requires that the branch circuit rating be at least 125% of the water heater nameplate rating. 210.2 says that Article 210 applies. 210.3 says that the rating of the branch circuit is equal to the size of the branch circuit OCPD. In this case the minimum size branch circuit rating that is permitted is 23.44 amps. That size OCPD does not exist, so the minimum rating of the OCPD is 25 amps. The maximum permitted OCPD for #12 is 20 amps in this case, so this circuit requires #10 wire and a 25 amp OCPD.
Don
- Location
- Massachusetts
Re: water heater
I do not see anything in article 422 that amends 210.3
You must use breaker greater than 23.44 amps for your example.
Bob
By the way your Caps Lock button is stuck.
[ May 25, 2004, 05:03 PM: Message edited by: iwire ]
You are correct the breaker is not part of a branch circuit, but as directed by 210.3 the breaker rating determines the rating of the branch circuit connected to it.
Section 2102 does not say "AN APPLIANCE BRANCH CIRCUIT IS NOT RECOGNIZED IN THIS ART." Section 210.2 says that other articles may amend or supplement the provisions of 210.
I do not see anything in article 422 that amends 210.3
You must use breaker greater than 23.44 amps for your example.
Bob
By the way your Caps Lock button is stuck.
[ May 25, 2004, 05:03 PM: Message edited by: iwire ]
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