I recently added some new, heavier-duty equipment to my garage
woodshop and am now finding that I'm tripping the breakers more often.
There are two circuits in the garage, both 15 amps. The new tools are
rated as high as 20 amps and trip the breakers under loads (no
surprise there). If I upgrade, should I just take these circuits on up
to 30 amps? Is this as simple as merely installing new breakers, or
will it likely require some rewiring? I don't plan on trying to do
this myself, but I would like to get a feel for what's involved and
how much it might cost. The house was built in 1978. I'll be calling
the electricians this week in any case.
If you have 15A circuits now, its likely you only have 14 gauge on
those 2 circuits. You have to re wire with 12 guage wire , and then
you can change out the breakers to 20A. Or you can just leave those 2
circuits alone and run a new 20A circuit. 30A is not really practical
for this application.
How far away is the panel? If its close, and if you can run new wire
to it with no problems, its fairly easy and straightfoward for an
average homeowner to do themselves.
* You will definitely need to upgrade the wiring to increase the amperage
capacity. I would suggest that you have an electrician install a subpanel
in your shop. This will allow you to easily add more circuits in the future
as you add more equipment. The subpanel topic and garage shop has been
discussed here a lot. Do a Google search of this group to see what has been
said in the past.
Increasing the wire size to 12 gauge (20 amps) or 10 gauge (30 amps) and
replacing the breakers accordingly will work. My guess is that adding
two circuits, rather than replacing the existing ones will be easier and
less costly. However, most higher current woodworking tools have motors
that can be reconfigured to operate on 240 volts. I'd suggest talking
with your electrician about adding at least one 240 volt circuit. Tool
performance will be a bit better. I now run my table saw, dust
collector, jointer, shaper and planer on 240 volts and find it
preferable to 120 volts.
Its a cliche that there's no such thing as a dumb question; but you strain
My mother once couldn't get the vacuum to turn on, so she untied a knot in
the cord to make sure the electricity could get through. And then admitted
to doing it.
Only if the wiring is of suitable size.
15 amps for #14AWG
20 amps for #12AWG
30 amps for #10AWG
The circuit breaker is there to protect the wiring as well as against
something faulty plugged in. Also your insurance company might not
honour your insurance policy if something happened! Putting in
breakers that are too big might SEEM TO WORK but is unsafe and not in
accordance with electrical code; and is the equivalent of people
putting a penny in place of a blown fuse. Lots of fires that way!
Also as some have mentioned if it is long run from the circuit breaker
box to the tool location, like 50 to 100 feet say. There might be
enough voltage drop on low gauge wiring (like #14AWG) to slow the
start-up of the tools and cause them to take too many amps for a
But trying to use a 20 amp tool on a 15 amp circuit doesn't make any
more sense than trying to put 7 people in a four seater car! Also not
using more than one tool at a time????
We have #10AWG 115/230 (3 wire plus ground) for a wiring distance of
less than 25 feet, to a sub panel in our workshop. It is fed from a 30
amp double pole breaker. The sub panel has 20 amp fuses to #12AWG
wiring to 115 and 230 volt outlets; because we have a few tools and a
couple of soldering irons that operate on 230 volts. Only time we have
occasionally 'blown' anything is when we have stalled a 230 volt bench
saw; and not always then. The sub panel is also a means of switching
off 'everything' in the workshop (except a row of lights on another
circuit) before leaving that room.
Please be careful.
Thanks to all for the kindly advice. I've turned the project over to
an electrician and will soon be circuit-overload free (I hope). I'm
sure my ignorance of this subject was clear to all. I'm at least able
to discuss the topic with the electrician now.
I was surprised by Jack's remark about my question on this subject
"straining" the old adage about "no such thing as a dumb question,"
and am wondering if maybe he's the "dumb-question designator" for the
forum? If so, he's doing a heckuva job. Of course, isn't this exactly
the place for ignoramuses like me to ask questions about home repair,
even dumb ones? If I knew the topic sufficiently, what's the point in
asking the questions?
Thanks again for the assistance.
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