I would like to install a Dayton, ceiling mounted, electric heater in
my 2 1/2 car garage/woodshop.
The heater runs on 208 or 240volts - 36.5amps - 7,500watts and puts out
What size awg wire would I need for this heater?
The wire will run from the main panel and hard wired to the heater.
Any advice will be greatly appreciated!!!
My workshop is an attached garage and I live in the Seattle area so
winters aren't all that bad here. Although, you wouldn't know that by
looking outside today! 6 inches of snow and and a low of 18* tonight,
this RARELY happens.
The distance from the main panel to the heater would be approx. 20-25
I have room in my 200 amp panel for a 50amp 2 pole circuit to power the
unit. This panel also powers the other lights/outlets in the garage as
well as the rest of the house.
I got an estimate of $3,000 to have a Reznor type natural gas heater
install, this includes the unit and piping gas to the garage. Since the
gas meter is on the opposite corner of the house, they would have to
pipe it over to the garage.
I talk to my gas/electric utility company about costs and this is what
they said. For $100 in natural gas, I would spend $156 in electricity
for the same amount of "power". So I realize that gas is a cheaper
Electricity costs me 8.6 cents per kilowatt hour. So to run a 7.5kw
heater will cost me $0.65 an hour to run. I'll run the heater 1-2 hours
per day, which maybe 4-5 times a week. This is how much I run my
23,000btu kerosene heater now. So in a month I'll pay between $13-26 a
month for electric heat.
The unit it self will cost me approx. $500 and I will hang the heater
and run the wire myself. I just need a qualified electrician to hook
the wire to the panel, maybe $100.
So I can spend approx. $600 to have the electric heater installed or
$3000 to go with gas.
That's why I considering electric heat. If I were in the shop all the
time, say 40 hours/week, then I would go with gas.
I believe the OP said that the heater was 208/240 volt. Most
residences do not have 208 volt service. For 7.5 kW, the 36.5 amp draw
should be for a 208 volt service. For a 240 volt service, 31.2 amps.
125% of 31.2 = 39 amps. He could use a 40 amp circuit in that case,
assuming no motor. Either way, I would strongly recommend using copper
wire, in fact, his local electric code may require copper wire to
heating units. A separate disconnect should not be required since the
panelboard is in sight of the heating unit.
It 'sounds' like #8AWG.
Wiring distance is not given. Is it a separate free standing
garage/woodshop building? Or attached to house?
Voltage drop/wiring distance?
Is/will there be other electrical wiring to that woodshop/garage area?
If so is it a separate service or are outlets, garage lights, shop
tools etc. also wired to other fuses/circuit breakers on the same main
panel? Cos there are some rules about having 'mixed' services in same
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