I live in an area where electrical inspections are not required when building a
house. Therefore, my breaker box was never inspected. This is what I do know
about the breaker box:
200 Max Amp
20 breakers installed:
* 4 double 20-amp breakers
(AC/Heatpump, Oven/Stove, Water Heater, Clothes Dryer)
* 16 single 10-amp breakers
6 breakers slots remain free (no breakers installed)
Our house has a two-car garage that is enclosed as a library and then an
additional one-car garage that is actually a garage. The previous owner did all
this work and in the process, he used the existing power for the library in the
one-car garage. Well, the breaker will blow any time I plug in a heater or any
power equipment in the garage.
Is it safe to add another 10 amp breaker to the existing main breaker and use
that line to power the outlets in the one-car the garage?
First you want to recheck what you have. Maybe they make 10a breakers, but
I haven't seen them; and 20a is too small for the items you listed.
Do you want to run a new circuit for tools, or split off the existing garage
outlets for a new circuit? Either is possible. Which is easier would
depend entirely on your construction.
My bad. You are correct.
1 x 80 amp breaker (AC/Heatpump)
1 x 50 amp breaker (oven/stove)
2 x 30 amp breakers (water heater, clothes dryer)
10 x 20 amp breakers (other appliances, various outlets & overhead lights)
5 x 15 amp breakers (various outlets & overhead lights)
1 x 15 amp breaker (unused ... took off panel and found that out)
Currently, I only have a freezer running in the garage. From time to time, I'll
be running a miter saw, table saw, or grinder. In addition, my wife runs a
variety of equipment for doing stained glass (soldering irons, drimmel, etc).
During winter, we usually have one or two portable heaters in the garage. I
eventually plan to install an in-the-wall AC/Heating unit.
I'd really prefer to just split off the existing garage outlets (two of them)
and add two more into a new circuit.
Is this an attached garage or detached? It makes a tremendous difference.
Let's assume it is attached.
You don't have enough juice to power an electric heater and anything else
at the same time. Do you have room in your breaker box for a 2-pole
breaker, and how hard is it to run another circuit to your garage?
It would be pretty cheap to install a 100A or 125A main lug panel (with 4
or 6 spaces) and run it off a 30A 2-pole breaker and run 10/3 wg cable to
it. This would give you lots of room for expansion, including the
possibility of adding 220V circuits for an air compressor, or electric
heater (etc.) And your table saw will run better because the voltage drop
will be lower when it starts or is under a heavy load. I've seen the
panels recently as cheap as $12; you'll have to install a ground kit for
another $2 or 3.
If you use a 40A breaker, you can run 8/3 wg cable. It is a lot larger
than #10 (obviously) and costs more, but it might be more flexible, I
dunno. The breakers will cost the same, and it will give you an additional
2 kilowatts of power to the garage that might be handy with electric heat.
You're going to need to run several new circuits from the main breaker box
to the garage, or else install a subpanel in the garage. It's a good idea
to have the freezer on its own non-GFCI circuit, so you won't wind up with
spoiled food if something else on the same circuit were to trip the
breaker. The table saw probably needs a 20 Amp circuit, which you could
also use for your other tools (you're not going to run them all at the same
time, are you?) Portable heaters usually run around 1500 watts, which means
each will need its own circuit. The in-wall heater/AC may need 220V--you
might as well run the wires for it while you're doing the other work.
Thank you! Using a new subpanel, how does the following look?
1 x 20A GFCI single pole - Freezer
1 x 20A single pole - For power equipment (table saw, etc)
1 x 20A double pole - For future 230V AC/heater wall-mounted unit
1 x 20A single pole - For remaining two outlets and one outdoor outlet
1 x 20A single pole - Overhead lighting
Using a 15A breaker and 14 gauge wire is a lot easier for the overhead
lighting. I'd also put the freezer outlet on the lighting circuit. DO NOT
put the freezer on a GFCI -- put it on a simplex outlet (indicating it is a
dedicated outlet) since it is not GFCI protected.
Use a GFCI duplex outlet for the first outlet on each branch circuit. It
will protect the whole circuit if you wire it right, and they are a lot
cheaper than GFCI breakers.
Just leave a double space in the panel for the heater circuit. You don't
know what size 2-pole breaker you'll eventually need. It could be anything
from 15A to 30A or maybe even 40A.
I have 4 circuits in my workshop, with no heaters!
Presumably the heaters are 1500w. Each should have it's own circuit, and you
need a circuit for your big tools. If you are careful, you can probably fit
the small things in those three circuits; though 4 would be nice.
I would give some serious thought to changing your heating now. Otherwise
you will have to add at least 3, preferably 4 circuits. Someone suggested a
subpanel. That is certainly reasonable for 4 circuits, though running two
multiwire circuits is an alternative.
Is your existing circuit 20a? If not, I wouldn't bother salvaging it
because you should have 20a circuits for the type of stuff you are running.
Even if you don't strictly need it, there is less voltage drop on long runs.
He says he has 4 double breakers, and details what they are for. None are
for the garage.
He says when he plugs his heater in the garage, it trips a breaker.
If there is no 240v in the garage, and he can plug his heaters in there,
they must be 120v.
He's either a licensed electrician, or, he's too embarrassed to be viewed
as quite that big an idiot ;-)
That being said, sometimes a milder expression of the same is justified if the
poster appears to be a bit too naive to be fooling around with electricity.
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.