Shop talk (literally)

[asp125]

Here's the question. I have an ~1000sqft garage to heat, so I can work on my bikes and cars over winter. There is 1x30A and 2x20A (240v) circuits on a 100A subpanel. I want to run a ceiling mounted electric shop heater. Thinking of using one of the 20A circuits to do that. OR should I use the 30A circuit and run a larger heater? Never had the luxury of anything more than 15A before.

[quasi]

Power requirement of the heater dictates what size circuit you will need.

[ARtraveler]

I would go with the bigger set up. More heat.

[jerpinoy]

Good advice on last post, add mine make sure the amps and circuit breakers(cb) and wire size requirements are met.

15amps CB and 14 wire size

30amps CB and 12 wire size

[JerryB]

Hi jerpinoy,

Re: 30amps CB and 12 wire size

Are you sure that you do not mean #10 wire size?

All of my 30 amp circuits require #10 wire. #12 wire is for a 20 amp breaker/circuit.

Jerry Baumchen

[Cabinkids]

Is the garage well insulated? Are you going to keep it heated all the time or just when your working in there ? An electric heater of that size for that area will be slow if you are only heating when you are in there. Kerosene. Or propane would be faster.

[Chupaca]

# guage wire amp breaker

14--------------------------- 15
12--------------------------- 20
10--------------------------- 30
8----------------------------- 40
6------------------------------55
4------------------------------70
3------------------------------85
2------------------------------95

I have only worked with the top three...never even seen a 2...

[TicketBait]

# guage wire amp breaker

14--------------------------- 15
12--------------------------- 20
10--------------------------- 30
8----------------------------- 40
6------------------------------55
4------------------------------70
3------------------------------85
2------------------------------95

I have only worked with the top three...never even seen a 2...

I have a 2 for my Tesla wall charger that was installed and the City and the electrician are arguing about it The board is a 90 amp, and the Tesla uses 72amps. The city says a #4 wire and wants the electrician to change it. In the mean time I am receiving free electricity untill it gets hashed out and Edison installs the meter

[SPYD3R]

have you considered a PROPANE heater...? much cheaper than electricity....
20160522_110440.jpg SAM_1120.jpg
as you can see at the top right of each photo, i had installed a propane heater...
at one time, i used a portable electric heater, sometimes 2 when it got really cold... with the propane heater, i've reduced my heating cost by half... i never left the electric one on over night, but i do set the propane unit on low, just in case my cats decide to sleep in the MAN-CAVE, and it never gets below 50 degrees on the coldest night...
i visited my local propane dealer, and the unit i have was a FLOOR MODEL, original price was $400, and i got it for $225 installed...
just an idea for you to think about...
good luck, and i'm sure you'll make the right decision that fits your needs....
Dan P
SPYD3R

[kep-up]

I have a 2 for my Tesla wall charger that was installed and the City and the electrician are arguing about it The board is a 90 amp, and the Tesla uses 72amps. The city says a #4 wire and wants the electrician to change it. In the mean time I am receiving free electricity untill it gets hashed out and Edison installs the meter

I'd say your city inspector is a joke. Why would he insist that you use a conductor that barely meets the load requirements when you already have a size that is much more than adequate? Stupid!

KENNETH CAMPBELL
fully certified third party construction code official and former master electrician

[Roadster Renovations]

That will cost big $$$ to heat for many hours. I have had a shop since '99 and we started out heating it with a wood stove, went to a used oil burner, and now heat it with a natural gas ceiling heater. In the office, which doesn't get as much flow as the rest, we have an electric heater. If it is run much at all it will raise the bill by $100 or more a month.
Cheapest heat would be an oil burner (if you have access to the used oil). Next best would be a wood stove. Gas would be the next after that. And electric would be the least choice.
Not sure of the hours you will be working, but a pellet stove that could do wood also might be a more economical choice.
Insulation is also key. The better insulation you have in the walls and ceiling the lower will be the radiant heat loss. R13-R-19, if possible,

[asp125]

The garage has wall/ceiling insulation. What R factor I don't know, not without opening things up or climbing into the 10ft ceiling. I was thinking of a unit like this: https://www.homedepot.com/p/Fahrenhe...H724/202043070 I guess that dictates the 30A 240V circuit.

Shying away from propane or gas because 1. no gas line to detached garage and 2. working with paints, possibly grinders and light welding, and 3. oxygen depletion at 7000ft elevation. Dunno, am I off base there? Actually been considering a pellet stove if it's enclosed, I have the room for one.

Not looking to work in there all day long, mostly to make it stay above freezing (say 45-50 degrees when vacant and bumping up to 65 when I'm working there).

[Lew L]

Are the garage doors well insulated??? I double insulated the doors of my 625 Sq Ft detached garage where the , V-Max, and shop are. Made all the difference here at almost 6000 ft elevation.

Lew L

[SPYD3R]

The garage has wall/ceiling insulation. What R factor I don't know, not without opening things up or climbing into the 10ft ceiling. I was thinking of a unit like this: https://www.homedepot.com/p/Fahrenhe...H724/202043070 I guess that dictates the 30A 240V circuit.

Shying away from propane or gas because 1. no gas line to detached garage and 2. working with paints, possibly grinders and light welding, and 3. oxygen depletion at 7000ft elevation. Dunno, am I off base there? Actually been considering a pellet stove if it's enclosed, I have the room for one.

Not looking to work in there all day long, mostly to make it stay above freezing (say 45-50 degrees when vacant and bumping up to 65 when I'm working there).

ASP
as for your #1; propane heaters use a 'bottle' and you can get them in various sizes, 250lbs up to many thousands... speak with your local supplier as to which would be best for your application... #2; i also SPRAY PAINT in my shop, and what i do is get the heat UP, turn of the unit OFF, paint, and switch the unit back on... in 12 yrs no issues... as for grinding/welding, there will never be an issue with those activities... now for your oxygen concerns, open a window or a door 1" or so once in awhile, but i wouldn't think you'd even need to do that... most buildings have so many small holes, that these would feed the building with fresh air...
just trying to save you a few buck$... electric heating is very expensive....
again, best of luck...
Dan P
SPYD3R

[Navvet]

Here's the question. I have an ~1000sqft garage to heat, so I can work on my bikes and cars over winter. There is 1x30A and 2x20A (240v) circuits on a 100A subpanel. I want to run a ceiling mounted electric shop heater. Thinking of using one of the 20A circuits to do that. OR should I use the 30A circuit and run a larger heater? Never had the luxury of anything more than 15A before.

The garage has wall/ceiling insulation. What R factor I don't know, not without opening things up or climbing into the 10ft ceiling......

Not looking to work in there all day long, mostly to make it stay above freezing (say 45-50 degrees when vacant and bumping up to 65 when I'm working there).

Not to throw a monkey wrench into the discussion, But you may want to consider another route. I put in a "Mini Split Ductless Heatpump" in my shop, my wife's shop, my neighbor's shop, ...... and several others.

MRCool has a DIY series that is a very reasonable, highly efficient heat pump and easy to install. The system is pre-charged so you just connect it up and run your power and you are done.

Just set the temp and your shop stays the same temp all year round.

http://ingramswaterandair.com/mrcool...4659_4661.html

The 1 ton requires a 120V 15 amp circuit (yes you could plug it into a wall outlet, but not recommended) and the 1.5 ton uses a 220V 20amp circuit.

I have a 750sqft (well insulated) shop and the 1.5 ton is overkill.

Just an alternative route to take for a shop ....

[H2O]

If you want to consider a gas furnace and have an outside wall with enough space to install it, look at a wall furnace with direct venting. I have an Empire wall furnace and there is one wall penetration for the inlet air and exhaust. It is a coaxial vent with the combustion air being drawn directly into the combustion chamber and the exhaust going out through a smaller vent pipe inside the combustion air pipe. The combustion chamber is sealed so you are not using room air (no oxygen depletion) and the exhaust vents outside so you don't have carbon monoxide concerns or excess humidity to cause rust on metallic surfaces.

H2O