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# how many heaters can i have

#1
02-16-10, 03:19 PM
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Join Date: Feb 2010
Posts: 3
how many heaters can i have

Hello all first post.

I am doing up my basement, or well trying. I have foam board insulation up studs, and floor done.

4yr old house with a cutler-hammer breaker box. there is 2 existing lrg heaters down stairs already, heater info now for both are OFM1250 - volts 240 watts 1250 amps 5.21. Both are the same and hooked up to 14/2 red wire to the elect box on a dbl breaker with info CH, BR420, DNPL220220, types BRD, A & DNPL, HACR type, 4 pole unit J969 E7819-T

Now i have no idea how many watts or amps i can have on this dbl breaker. And by dbl i mean 4 breakers in all 2 in the middle hooked together and the 2 outside hooked by a sort of guard thing.

i have installed plugs and lights before so im not new to electrical but heat i never touched before.
My main idea is to take the other large heater and put in the room so there will be lots of heat possible in there. get a smaller one (750 watts, 3.31 amps)for the washroom and maybe another large for the other area of the basement.

so i guess to sum up
total watts 3x1250= 3750 + 750 = 4500
total amps 3x5.21= 15.63 + 3.31 = 18.94
is this ok or should i put in another breaker.

oh not sure if this matters but 2 heaters in the rm will be on its own thermostat 1 in the washroom and 1 for the other area.

#2
02-16-10, 05:27 PM
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Welcome to the forums!

You may load a 20 amp circuit up to 16 amps continuously (load running more than 3 hrs which your heaters will be) and a 15 amp circuit no more than 12 amps continuously. Use these numbers to figure how many heaters you may have on a circuit.

The breaker will have a number on the handle 15, 20 or 30 amps. You must use #14 for 15 amp circuit, #12 for 20 amp circuit and #10 for a 30 amp circuit. I would suggest not using a 30 amp circuit for ease of wiring.

#3
02-16-10, 06:36 PM
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Originally Posted by pinsent
Hello all first post.

I am doing up my basement, or well trying. I have foam board insulation up studs, and floor done.

4yr old house with a cutler-hammer breaker box. there is 2 existing lrg heaters down stairs already, heater info now for both are OFM1250 - volts 240 watts 1250 amps 5.21. Both are the same and hooked up to 14/2 red wire to the elect box on a dbl breaker with info CH, BR420, DNPL220220, types BRD, A & DNPL, HACR type, 4 pole unit J969 E7819-T

Now i have no idea how many watts or amps i can have on this dbl breaker. And by dbl i mean 4 breakers in all 2 in the middle hooked together and the 2 outside hooked by a sort of guard thing.

i have installed plugs and lights before so im not new to electrical but heat i never touched before.
My main idea is to take the other large heater and put in the room so there will be lots of heat possible in there. get a smaller one (750 watts, 3.31 amps)for the washroom and maybe another large for the other area of the basement.

so i guess to sum up
total watts 3x1250= 3750 + 750 = 4500
total amps 3x5.21= 15.63 + 3.31 = 18.94
is this ok or should i put in another breaker.

oh not sure if this matters but 2 heaters in the rm will be on its own thermostat 1 in the washroom and 1 for the other area.

Ok, first of all, check that wire again. If it really is 14/2, and it really is a BR420 breaker unit, (20A/20A tandem double pole), you have a serious problem. Especially since these circuits are feeding heating units. 14ga wire can only be on a 15A breaker. A 20A breaker requires 12ga MINIMUM.

As it stands, (assuming you were mistaken and it is 12ga wire), that circuit is maxed out and will not support another heater, regardless of the wattage.. If it is 14ga wire on a 20A breaker, then it is already overloaded by more than 3 amps, and you have a fire just waiting to happen.

#4
02-16-10, 07:58 PM
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Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
JerseyMatt:

Let you know the OP is from due he mention red wire { red cable }

To OP

You need to deal with breaker size with 2.5mm² { 14 AWG } it only can use 15 amp breaker not the 20 amp breakers

the only way you can slove it is replace with correct breaker size.

Merci,Marc

#5
02-16-10, 08:22 PM
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Join Date: Nov 2009
Location: wisconsin
Posts: 415
does each heater currently have its own wire running to the breaker box and have its own breaker handle or are they combined on the same wire and handle?

#6
02-17-10, 03:51 PM
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Join Date: Feb 2010
Posts: 3
thanks for the replys
sorry it is 12/2 red wire. NOT 14/2 like i mentioned.
the breaker has 4 switches in total. on each switch it has a 20 on it. the outer 2 are for the heat the middle 2 are for the hwt.
Both the outer are joined so when you turn one off the other has to go off as well. and the same for the middle 2

so i think. its either 20amps i can put on the wire. or well less then that or 40. if its 40 i dont think there is anything to worry about unless i put a lot of them on it. if its 20 amps, the total for the 4 heaters is 18.94 amps which i think is too close. unless i went with some other way to do it.
Like use 1 lrg heater and 3 smaller ones. I can always keep the other large one for my next house.
If i do that the amps on the 4 would be (1lrg3sml) 15.14 amps

pls let me know if its ok for that much or if its a 40amp cause of 2 20's with the 12/2 wire.

thanks again all.

#7
02-17-10, 04:29 PM
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That breaker is what's called a tandem double pole. Tandem (half handle) breakers are used to save space in order to use a smaller (read: cheaper) panel during construction, or to add circuits to a panel that is already full. They basically fit two breakers into the space of one.

A double pole (two handle) breaker is for controlling a 240v circuit. In your breaker panel there are two 120v legs. Each numbered breaker slot is on the opposite leg of the feed. (ex: in the left side, breakers 1, 5 and 9 are leg A, and 3, 7 and 11 are leg B) So when you need a 240v circuit (such as for your heaters), the double pole breaker (which takes up two numbered slots), provides a feed from leg A and a feed from leg B to make 240v. The handles are tied together so that if one leg trips or is turned off, the other leg turns off as well.

The tandem double pole is simply a combination of these two types. It fits two 240v (two handle) breakers into the space of one. Those four separate 20A handles would normally take up four separate numbered slots in your panel. With this special breaker, they fit them into two numbered slots.

To answer your other question, even though there are two 20A breakers per circuit, it is still only a 20A circuit, but at 240v. As long as the total load is 16A or less, you can use whatever combination you want. With the 1 lg and 3 sm units, you are OK with about an amp to spare.

(I tried to word this as simply as I could, if it's confusing to you, let me know! )

#8
02-17-10, 04:50 PM
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Join Date: Feb 2010
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awesome thanks for speaking to me like im 10yrs I need it when it comes to this. lol

That answers it now that i was able to give out the proper info .thank you.

side question. now that i can have 3sm and 1lrg. what about the thermostats. do that put a load at all? or not enough to worry about?

#9
02-17-10, 05:08 PM
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Mechanical thermostats are simply switches. They use no electricity. An electronic/digital thermostat uses a negligible amount. If you are usung the dial thermostat that's built into the baseboard, then there's nothing further to consider. If you will be using a wall thermostat and wiring multiple baseboards together to operate off one thermostat, then you have to check the specs of the stat to make sure it can handle the load that you want to control. In most cases with multiples, you would install a relay module into each baseboard (in place of the built-in thermostat), and the wall thermostat would be wired to activate all of the relays, rather than the full load of all the heaters.

#10
02-17-10, 09:23 PM
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"hooked up to 14/2 red wire to the elect box on a dbl breaker"

What's this red wire? You already explained it was 12-2 and not 14-2, but what kind of wire is this? I have never seen red romex. Are there any markings on it? It sounds like fire alarm cable which would be a major problem.

#11
02-17-10, 10:48 PM
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There's no such thing as 14 or 12 ga FPLR. I believe the heaviest it comes is 18ga. From the very little I can find, it may have been a UK color scheme up till a few years ago. Red jacket, with red and black conductor insulation.

#12
02-17-10, 10:52 PM
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Red NM cable is a Canadian thing. That sort of cable is the same as the yellow 12/2, except it has a red instead of a white. It is typically used for baseboard heaters, water heaters, and other 240V only loads.. They also make an 8/2 version, I suppose for feeding A/C compressors.

#13
02-17-10, 11:27 PM
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yeah... what he said!!

#14
02-18-10, 09:22 PM
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Originally Posted by JerseyMatt
There's no such thing as 14 or 12 ga FPLR. I believe the heaviest it comes is 18ga. From the very little I can find, it may have been a UK color scheme up till a few years ago. Red jacket, with red and black conductor insulation.
Simplex and Notifier fire alarm systems typically use 18-2 red fire alarm cable for initiating circuits and 14-2 red fire alarm cable for signaling circuits (I believe 12-2 is also available).

#15
02-18-10, 10:44 PM
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Originally Posted by CasualJoe
Simplex and Notifier fire alarm systems typically use 18-2 red fire alarm cable for initiating circuits and 14-2 red fire alarm cable for signaling circuits (I believe 12-2 is also available).
I was not aware of that. Any fire wire I've ever seen or worked with is 18 or 22ga. My bad. But I highly doubt FPLR was used in this siuation. Most likely it's a Canadian install, as classicsat said. Beer 4U2

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