In article , RBM wrote:
If you're running cable, you'll need 6\2g or if you're running conduit and
THHN you can use #8


"Roy Fek" wrote in message
oups.com...
Hello,

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
25,600BTUs.

What size awg wire would I need for this heater?

The wire will run from the main panel and hard wired to the heater.

As I remember, 10 AWG is good for 30 amps with me remembering a bit of
talk for 25 in some cases, 12 is good for 20 amps, 14 is good for 15
amps...

Sounds to me that 8 AWG is the minimum size for likely next step up of
40 amps...

Checking Google...

http://amasci.com/tesla/microtc.html despite unlikely URL shows a page
that appears to be one of a local government website showing wire size
rules that appear to me to be usual/nationwide-USA. First paragraph shows
intent to comply with NEC.

The above page indicates 8 AWG sufficient for 40 amps.

However, I remember from some recent past reference to some NEC tidbit
that a continuous load should not have current draw exceed 80% of circuit
ampacity. I consider a heater to be considered more a continuous load
than an intermittent one. 36.5 amps exceeds 80% of 40 amps but is less
than 80% of next step up of 50 amps, which requires 6 AWG wire according
to the above page in the likely event that the above heater gets to be
considered a continuous load.

--
- Don Klipstein )