Any electricians out there?

[justin13703]

So, I have a question that I can't really get a straight answer to. I recently installed two 8ft baseboard heaters on the rental side of my house. They are both on the same circuit, controlled through a wall thermostat to kick them both on and off at the same time.

So here is how the circuit is layed out. Double 20 amp breaker to provide 240 volts. All the wiring is 12/2. From the breaker, out into the thermostat. Then out of the thermostat, into a junction box. The wire then splits into 2 12/2 lines, one for each heater.

My issue is, each heater is 10.5 amps. There is a total load of 21 amps on the section of the circuit from the breaker, to the junction box where it splits. From what I've been told, 12 gauge wire is rated for 20 amps. Once the heaters run for a while, the section of wire before the junction box will get a little warm. Not hot, just a little warm. So I am wanting to replace the run of wire from the breaker to the junction box with 10 gauge, and leave the 12 gauge running to each heater, because 12 gauge is plenty thick to run the 10.5 amps that they will be carrying.

Is this ok to do? I've heard yes, and I've heard that if any part of the circuit is 10 gauge, it all has to be 10 gauge. I'm thinking it should be fine, because the wire will be correctly sized for the amperage it will be carrying at each area of the circuit, and it is a dedicated circuit for the heaters, nothing else will ever be added. I really would rather buy a 50ft roll of 10 gauge to replace the 21 amp load section, than buy a 250 ft roll for 200 dollars and rewire the whole circuit with it.

Thanks to anyone with any help

 

[trdtoy]

More amps or more wire length will require larger wire to work properly. What you are wanting to do may work however you need to see what code is for this in your area and discuss with local trusted electrician for your best answer. This may be why you are getting two answers as both may work but one is to code.....

 

[TRON]

Electric baseboard heaters are considered a "continuous load" in the NEC. Therefore, the total amperes for each unit must be multiplied by 125%. This gets you a total just over 26 amperes.

I'm surprised that your circuit breaker is holding... Hopefully your electrical panel is safely installed.

I would recommend getting an additional double pole 20 amp breaker and run an additional 12/2 run to the junction box. That way each baseboard heater; which are pulling 13.125 amperes each, will be on their own dedicted 240 volt circuits. Home Depot sells 50 ft rolls of 12/2 romex.

You are right... 12 AWG wire is rated for 20 amperes; however, this load is continuous. Therefore you must decrease the ampere rating to 80% which would be max of 16 amperes.

 

[justin13703]

Is there a way to wire them both on their own but still have them running off of the wall thermostat?

 

[justin13703]

And what about what I was thinking about running the first section from the breaker box to the junction box in 10 gauge? I don't see how this would be a problem as long as the breaker is sized for the 12 gauge wire and nothing else is added to the circuit.

I also noticed last night, I turned them on for about 2 hrs straight to see what would happen. It took about a half hour for the wire to warm up to the point that it was noticeable, and then within a half hour after that, it was completely cool again, and yes the heaters were still running. Does this mean that they draw a bigger load while they're warming up and then once they get there the amp draw drops down a little bit?

 

[TRON]

As for the thermostats; they do make individual end kits that attach to either side of a baseboard heater. There maybe a dual thermostat device as well; not sure about that. Or you could easily have 2 wall thermostats next to each other.

As for the proper wiring; My reasoning is purely based on the NEC code. And these codes are set for your liability and safety.

 

[justin13703]

As for the thermostats; they do make individual end kits that attach to either side of a baseboard heater. There maybe a dual thermostat device as well; not sure about that. Or you could easily have 2 wall thermostats next to each other.

As for the proper wiring; My reasoning is purely based on the NEC code. And these codes are set for your liability and safety.

I can't do the thermostat on the ends of the heaters because of their location. And it would be a little weird to put two thermostats on the wall right next to each other lol. As far as the code, I don't see how there could be a code violation on running 10 gauge to carry 21 amps, then split it in a junction box to two 12 gauge wires carrying 10.5 amps each, while the breaker is sized for the 12 gauge wire. The 12 gauge won't overheat because it will only be carrying 10.5 amps, and the 10 gauge obviously won't overheat because not only is it carrying only 21 amps, but the breaker would blow long before 10 gauge would be overloaded. That's my main point in question

 

[kwigs160966]

Honestly you should hire an electrician to do the work for you. As a journeyman electrician I don't recommend that anyone attempts there own electrical. Some electrical is easy enough but you have to have an understanding of so many different subjects. When it comes to electrical contractors its one thing to know the code bOok and another to know building codes and requirements.

How many watts are these heaters rated for?
What information is on the name plate, like amps and voltage.
As stated before these are continuous loads.

You want to make sure that everything is correct especially in a rental property you don't want to risk a fire or someone getting electrocuted.




What is the temperature rating of the wire you are using? And what does it say the minimum temp rating is on the heater?

 

[justin13703]

Honestly you should hire an electrician to do the work for you. As a journeyman electrician I don't recommend that anyone attempts there own electrical. Some electrical is easy enough but you have to have an understanding of so many different subjects. When it comes to electrical contractors its one thing to know the code bOok and another to know building codes and requirements.

How many watts are these heaters rated for?
What information is on the name plate, like amps and voltage.
As stated before these are continuous loads.

You want to make sure that everything is correct especially in a rental property you don't want to risk a fire or someone getting electrocuted.




What is the temperature rating of the wire you are using? And what does it say the minimum temp rating is on the heater?

I had an electrician that does all the electrical at my place look over it and said everything was perfect. The only thing in question was if this slight warmness of the wire was going to be a problem.

The heaters are 240 volts, 10.5 amps each, 2500 watts each.

Here is a link to the wiring that was used:
http://www.lowes.com/pd_70111-295-2...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=

Here is a link to the heaters that are installed:
http://www.lowes.com/pd_23255-1509-8F2025W_1z0z87u+1z0zq4q+2z8vn__?productId=3132701&Ntt=baseboard+heaters&pl=1&currentURL=%3FNtt%3Dbaseboard%2Bheaters%26page%3D1&facetInfo=Cadet|$50%20-%20$100