Would you prefer 15a or 20a ocpd

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mark32

Senior Member
Location
Currently in NJ
This is so dumb I almost don't want to ask it but I'm just curious as to what you guys would choose. I maybe wiring an 8' electric baseboard heater. After figuring in the continuous load increase it will draw roughly 10.5 amps. I'll pull #12 to it and protect it with a 20a breaker but would it be better to use a 15 instead? What would be a better choice?
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
101111-1305 EST

#14 is 2.53 ohms per 1000 ft at 20 deg C. Power dissipation in 1000 ft would be about 300 W. If the baseboard heater is 50 ft from the breaker panel, then about 30 W is dissipated over that 50 ft or 0.6 W per foot. Adds a little heat to the building spread over the path to the baseboard unit, and may not be wasted heat.

.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
This is so dumb I almost don't want to ask it but I'm just curious as to what you guys would choose. I maybe wiring an 8' electric baseboard heater. After figuring in the continuous load increase it will draw roughly 10.5 amps. I'll pull #12 to it and protect it with a 20a breaker but would it be better to use a 15 instead? What would be a better choice?

Better is a very subjective thing.

It will cost slightly more so in that respect it is anti-better.

Some might think that allowing more room for potential future loads makes 20A "better".

The heater is not going to care.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This is so dumb I almost don't want to ask it but I'm just curious as to what you guys would choose. I maybe wiring an 8' electric baseboard heater. After figuring in the continuous load increase it will draw roughly 10.5 amps. I'll pull #12 to it and protect it with a 20a breaker but would it be better to use a 15 instead? What would be a better choice?

Mark, it doesn't matter. The only reason I pull #12 is so that if we need to add to the circuit we have a little more play. If that is the only unit then #14 is fine.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Just because the wire is #12 it doesn't mean you HAVE TO use a 20A breaker. A 15A breaker would technically provide closer protection for the heater, but in reality a baseboard heater will only draw more current if there is some serious problem, so most likely any breaker would trip on Short Circuit rather than thermal anyway. In short, dealer's choice.
 

mark32

Senior Member
Location
Currently in NJ
As an EC there will never be a ROI to provide 12 AWG when 14 AWG is suffecent for this application.

True true, using 14 didn't cross my mind as I have some 12 I'd like to use up but great point.

I guess my question boiled down to protecting equipment properly. On a dedicated line installing a 15a breaker on something that draws 10 sounds better to me than using a 20 but in some cases, such as this heater, it probably doesn't matter much.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
It's really no different than a fully-loaded 20a circuit on which only one small heater is turned on.
 
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