Hi all.. New to the forum.. Thanks in advance for any help..
I am trying to set up new baseboard heating in my basement.. My questions are to what size breakers to use and if I can put it all on one circuit..
I want to set up 3 rooms:

room 1 - 2 1000 watt heaters
room 2 & 3 - 1 1500 watt heater
plus a small hallway - 1 500 watt heater..

They come up to a total of about 25 Amps..
Can I just get a 40 amp dual pole breaker and put it all on one circuit w/ one thermostat?? What size wire? Is 10 size wire enough? Thanks for any help!!!

John

Fr_Chuck

Did not say 120 or 240 so that is a difference
also was that a 1500 in both room 3 and 4 or was it one for both rooms

Ok, where are you getting 25 amps

watts total

room 1 1000
room 2 - 1000
room 3/4- 1500
hall 500

4000 total watt / 120

33.33 amp

I come closer if I figured 240 vt with a heater in both room 3 and 4

Not a electrician, but a math person

slym34

I got 25 amps from adding the amps on the sides of the boxes (and I rounded up a little)...
It is 5 total heaters (yes 1 in each of those rooms for the 1500)
2 - 1000
2 - 1500
1 - 500

5500 total

Using 240.. So do I just divide 5500/240? that equals almost 23 amps... I was told not to max out the breaker so I'm thinking maybe a 40 2 pole would work?! All on one circuit ok?? The guy at home depot said I had to set up all different circuits w/ all separate thermostats.. He wanted me to get 4 thermostats.. I didn't think that was right... Then need to know what size wire.. Thanks for the reply!

tkrussell

I get:
Rm#1-2000w
Rm#2-1500w
Rm#3-1500w
Hall -500w
Total-5500w @240volt=22.91 amps needs a 30 amp circuit with all #10 copper wire.

slym34

that is what I had thought I could do, but the dope at HD said I had to run 4 separate circuits... Just needed some reassurance. Thanks!

ps.. Is there a calculation on what size wire to get? why 10 instead of 12 or 8 etc.. Thanks!

John

tkrussell

Wire size comes from NEC Tables in Sec 310, and may be found at wire manufacturers websites. #10 Romex,BX, MC cable is all rated 30 Amps.

Loads shall not exceed the running amps plus 25 %, 5500x/240v= 23 amps+25%=28.75Amps, next standard size wire is #10.

The only draw back to this is that you must use #10 wire thru out the circuit.plus if there is ever a problem with the circuit the entire heat system is out of commission.

I would run two 20 amp 240 volt circuits, split the heaters up in any fashion. Much easier to work with #12 cable, take my word for it. #10 solid wire is very stiff, and prone to bad connections on the heat devices. i would have more than one stat also, one for each room and the hall is on the living room circuit.

slym34

So if I am on 20 amp circuits I can go back to 12 wire? So If I put

1 20 amp circuit:
2 1000 watt for big room and 1 500 watt for small room on one thermostat:

2500/240= 10.4.. So a 20 is fine..

Then another 20 amp for the
2 1500 watts for the other 2 rooms, 3000/240= 12.5, one one more thermostat.. That'd be ideal so I can go back to 12 wire correct?!

tkrussell

Exactly. Use deep wall cases for the tstat boxes, the heat you just need a two foot tail at each heater, assuming baseboard units. Be sure to ground everything, tstat if there is a green screw, and each heat unit. Two 2 pole 20 amp breakers , done.

slym34

Not sure what a deep wall case is?!?!
Also what about the 2 foot tail? What does that mean?
They are baseboard units yes..

tkrussell

Wallcase is an electrical box named wall case, find them in the outlet box aisle.

Tail is the end of cable left during rough in, leave two foot at the general area of the heater, then drywall with the tail hanging out. Trim the cable once you are ready to connect to the heat unit.