hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have 750W baseboard heater 120V breaker is sized at 20A is that not oversized? Normally 750/120 * 1.25 = 7.81A.
NEC baseboard
- Thread starter hhsting
- Start date
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Breaker is sized to protect cable, not heater. You can downsize if you wish.
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
424.4 (2020) says branch circuit can supply any wattage rating for which the branch circuit is rated
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Thanks but we are in NEC 2014. It does not have 424.4
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Actually it’s in NEC 2014 424.3(A). So if I have 120V 20A breaker branch circuit then I guess branch ckt is rated 2400VA. If I have heater that is 2400VA at 120V then I can install it?
Isn’t space heater continuous load? So how can what you say apply when branch ckt sizing is considered continuous load?
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
120 volt 20A circuit can supply 2400va but not continuously. 1920va continuously
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
If what you and all of you is true then what’s to stop one from providing 30A, 35A, 40A, or 50A breaker with #8 AWG cable to 750W single phase 120V heater? Their is no max size
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Branch circuit for a residence cannot be over 30 amps if more than one heater is used. Cost will usually stop someone from over sizing the conductors. You do need to multiply by 1.25 for the conductor size minimum
It is important to note 424.3 notes that branch circuits for space heating shall be sized as a continuous load.
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