The previous owner had installed one 220 volt outlet in the garage. However, I
need another two 220 volt outlets. I will be using only two 220 volts outlets at
any one time, including lighting. That is; I will be running a 2 HP dust
collector (about 10 amps) and a 1-1/2 HP (10 amps) table saw, jointer or planer
(both 220volts max 15 amps).
I am thinking of installing a 60 amps subpanel myself for three or four 220
volts 20 amps and a few 110 volts outlets for small hand tools and lighting.
The distance from the main electrical panel to the garage is about 50 feets. To
save cost, should I run the wire (what gauge?) from the main panel to the
subpanel in the garage and then let a cerfied electictian to hoke it up gfor me
test and certify it? I am by no mean an expert in electrical, know a bit but not
Thanks, I als appreciate other suggestions.
Is the garage attached or detached from the the house?
Based on your apparent knowledge level, the best thing you could do is
provide a path for the electrician (either dig the trench to his specs or
create a path through the house [drill joists, poke through blocks ]), then
let the electrician do it.
Odds are a 100 amp panel will be the best buy, the electrician can feed it
at 100 amps just about as cheap as a 60 amp.
He's not gonna garantee either your conduit or your wire in the conduit, let
him provide both (a nick that goes short is easy to do).
You can save by providing the path and managing the inspections. (You call
and be there when the trench, rough-in and final are done, the electrician
will still correct any faults).
Are you sure your DC is 10a? That is an awful lot for a 1.5hp motor.
How many amps is your existing outlet?. If your DC is only 8 or 9 amps,
then you can just add an outlet to the circuit if you have a 20a circuit.
You might want to try that first anyhow to avoid the expense of a subpanel;
they generally don't pull their full load for very long, if ever.
I'm only estimating it at 10amps. If I remember correctly it should be around 7
The house have a 200amps main panel. The garage have only one 220volts 20 amps
circuit outlet, connect from the main panel and five 110volts outlets from
??? what do you mean? I already have an 220/20amps circuit in the garage and
think of adding another two 220/20amps circuits.
I am debating whether to pull one 60 or 100 amps subpanel to the garage or pull
two 220volts/20 amps circuits to the garage. Which is cheaper and simpler?
I have already bought one coil 250 ft, 12/2 gauge wire, two 20 amps panel
switches, I could just keep it or sell in a garage sale later if I decided to
install a subpanel, no big deal.
You now have a single 240v/20a circuit. Is there anything on it at present?
If not, and your DC is only 7a, then there is no problem putting the DC and
table saw on it. A table saw only draws full current when it is straining.
Hopefully that is rare and for very short durations. So, if your TS is 10a,
and your DC is 7a, you have a good margin on 20a circuit.
You say the jointer and planer are both 240v also. Presumably they are less
than 10a, and you will not be using 2 tools simultaneously, so you are in
good shape. All you have to do is install a few more outlets on the 240v
circuit. I expect you could actually have two tools running, as long as
they were not actually cutting/planing/jointing material at the same time
(even then, you can likely get away with a few seconds overlap.)
Your bigger problem might be the 120v. You say you have one circuit. Is
there anything on it at the moment, such as lighting? What size is it? If
you have lighting on it, and it is only 15a, then you will have problems
with a large router; for instance. If it is 20a, or you have a separate
circuit for lighting, you might be okay; though a clean 20a would certainly
be nice to have.
Running a single circuit, 240v or 120v, is pretty easy. Installing a
subpanel is a lot tougher. The components are much more expensive and the
cable is much more difficult to run. But I can't see you needing a subpanel;
at most a single 20a 120v circuit, if I understand the situation properly.
My present TS is 1 HP, 110/220volts, 14/7 amps, wired to 110volts. Each time I
turn on the TS, all the fluorescent lights blinks. When I rip a thick lumber the
breaker trip in the main panel. So I will have to replace the 1HP with 1-1/2hp
and rewired it to 220volts.
My present only 220/20 amps circuit in the guage mare not in use, except for the
planer/jointer/compressor, in the far side of the garage. I don't want to extend
the TS's wire to that 220/20amps outlet.
I believe I could wired the single 220volts 20 amps to two outlets, with only
one being use at anyone time. The dust collectors (1 or 1-1/2HP) had to be on a
220/20amps circuit together with lighting(?), as it draw 9 amps. connecting to
the TS will be at stretching my luck, and I may have problems again on thicker
This is probably my main concern, it is connected to my bedroom light and 4
outlets, I will definitely need an electrician to rewired it as a separate
circuit. All the garage's fluorescent lights will have to draw from the garage
sub-panel, maybe from the dust collectors curcuit?
As you can see I really need a subpanel or at least draw two 20/2 gauge wire
from the main panel to the garage. The question how to do it with min. cost and
would do all the dirty work and let the electrician connecting it together and
sign it off. How would you suggest I come about doing it? Like where to get the
City/County code and etc.? How much do you think it cost, like max and min?
The last time I ask a plumber to check and replace the thermostat on my water
heater, he charge me $80 for 10 minutes work. After that I do all my own
plumber, lighting and replacing the 40 gallons gas water heater all by myself.
However, I am a bit afraid when doing electrical, wanna careful especially when
I have never install new wiring to main panel.
Thanks, please do advice more....
If your only 120v circuit is connected to both your garage lighting and your
bedroom then you have to do something.
Putting in a 60a subpanel will certainly solve all your needs and provide
for any conceivable future plans. The hard part is running the cable; it is
thick and doesn't want to bend. I don't know if any electrician would be
willing to simply make connections on your wiring, but if he is, it couldn't
take more than an hour or two. Properly speaking, you probably should get
it, and any branch circuits, inspected, but I don't know how many electrians
would bother with it.
But I think that is overkill. Your existing 240v circuit will power your
DC, TS (when changed to 240v), planer, jointer, and compressor; as long as
you don't use more than 2 at a time. If the existing outlet is at the far
side of the garage, then cut the cable and run it to a new outlet or four
where you want it, and then run a cable from the new outlet to the existing
outlet. Unless you have a finished garage, that should be pretty simple.
Your observation that the breaker only blew when you were cutting a big
piece is because the motor only take a fraction of its maximum unless it is
straining. That is why I say you can probably run 3 tool at once if you
wanted, as long as they were not all straining at the same time.
240v suffers less from voltage drop than 120v, so a long run isn't as bad as
it would be on 120v; plus, two tools aren't likely to surge at the same
time, so surge voltage drop is less of a problem.
I have my 2hp TS and my 1.5hp DC on a 20a circuit and they purr like
Leave the lighting on the old 120v circuit. Run a new 20a 120v circuit to a
few new outlets for small tools. If you think you need more than that, then
run a 120v multiwire circuit. It is not much more work or expense, but
gives you twice the power. One thing you will have to think about is GFCI
protections. That is required for all 120v outlets in a garage except for
outlets used for things that cannot be readily moved such as a table saw, or
for outlets that are out of easy reach, such as those for garage door
If you really want a subpanel, then go for it; but unless I am seriously
misunderstanding something, it is not necessary.
I have been wanting to get an electrician to fixed that damn circuit. I guess
the previous owner merged the bedroom and garage circuits together. I must be
honest, I'm not confident in troubleshooting or fixing that problem.
Getting an electrician to do what i wanted is the problem. I have called at
least two electricians and they never show up to give me a quote. That's why I'm
here to squeeze as much information before starting. I am getting the Band saw,
dust collector and drum sander early spring... getting desperate.
Ah another woodworker! I have a finished garage. I really doubt I can run 2
machines at any one time on the 220/20 amps circuit. I can try next week if
weather permit (I still need to finish my WIP snow thrower's carburetor). Even
if I could I will still wanna have at least two or more(prefer) 220/20amps
circuits in the garage, bearing in mind the dusts collector will be on all the
Thanks for telling me of the GFCI and will incorporates into the panel/wiring.
Let say I insist on it, will it be much easier than pulling two or more wires
into one or more 3/4" conduits for 50 plus feet in a finished garage? I don't
think the cost will be any much more than an additional 60/100amps subpanel. By
the way I still have space for two 220/20amps breakers in the 200amps main
Anymore ideas, suggestion or another routes appreciated. Thanks.
A finished garage will be more difficult, but no difference between
rerouting the exising circuit or bringing in a new one.
Why do you doubt you can run 2 machines on a single circuit?
Why do you want conduit? Some local codes might require it, or you might
have a protection problem, but otherwise 6/3 cable will likely be easier and
cheaper. (Aluminum 4/3 is cheaper still, but I am not about to recommend
If you have a straight run with no obstacles, then it really doesn't matter
what you use. If there are holes to drill (maybe dozens of holes to drill)
and bends to make, then a pair of 12/2 will be a heck of a lot easier than
the panel requirements.
I just ran a 12/2 from one end of my basement to the other. It took about 3
hours. (it would have taken maybe an hour if I had ignored code) 6/3 would
have taken all day, and I don't think I could have done conduit; I thought
about running a gas pipe along the same route to my laundry room and decided
it was impractical.
A friends garage has the 2Hp DC on a 15 amp 220 circuit, and his 3hp saw
on a 20 amp 220, on a 60 amp sub-panel in the remote garage.
I'd suggest putting in a 60 amp sub-panel, then the controls (breakers)
will be in your shop, which makes things safer when you can see that
nobody is flipping breakers on behind your back.
One thing to note, with this arrangement, there is no flicker or
noticeable effects, in the house, based on what is done in the shop.
GFCI's work fine with woodworking tools, never had a problem with trips
in my basement shop.
Again, a sub-panel will allow you to have 220 circuits and 120 for tools
and lights and tv/radio whatever.
Flexible conductor wire is much easier to pull. No problems pulling 4
#6 wires through 3/4 rigid (thicker for underground) conduit. (I pulled
a full rated ground cause I'm a belt and suspenders man when it comes to
not getting shocked).
Big problems trying to pull 3 stranded and one solid #6, in another
application inside, you know, unified ground stuff. yuck go with
I didn't think you could use solid #6 in conduit?
I'm about to pull three #6's in a 3/4" EMT conduit for the service entrance
conductors to my detached garage; I'd rather use two #6 THHN stranded wires
and one #6 bare solid copper but I thought the code book says anything
larger than #10 had to be stranded if used in a raceway, except where
specifically allowed elsewhere in the code (and I couldn't find anywhere
else that mentioned it)
I have enough solid #6 in my odd-and-ends box to do the job, but I'll have
to buy the insulated stranded #6 for the hot conductors. Plus it is real
obvious which conductors are hot and which are grounded at the ends of the
conduits without having to put white tape on one of the wires.
When I talked to the inspector a couple of months ago, he didn't think you
could use a bare wire in conduit, but the code book specifically says you
can use it for a grounded conductor.
I think you are correct, although I don't know the section that mandates this
There are limits to this, and you can only use bare neutrals where specifically
allowed by the code.
Otherwise we could use the a bare wire for clothes dryer, range, and feeder
neutrals, but I know
this is not allowed. I'm not convinced you can use a bare neutral in this
application unless you are
tapping your service conductors prior to your main disconnect.
I would encourage you to run a 4 wire feeder to this structure anyway unless you
know you'll never
want phone, CATV, network, or other cables or metal pipes going to that
building. The 4th equipment
grounding wire can certainly be bare or green, but may need to be stranded
because of its size.
I'm using triplex overhead wire between my house and the garage's service
conduit. I'm reusing the abandoned old service entrance conductors at the
house to feed the triplex, so there is no 4th wire unless I want to pull
new wires through the old 3/4" conduit -- I don't know what kind of bends
and/or pull boxes might be in the 50 year-old conduit, but they would be
inaccessible. I also don't think you can put four #6's in a 3/4" conduit
without exceeding its maximum "fill", but I'd have to look it up.
BTW, I'm backfeeding the old service conductors through a 60A 2-pole
breaker for my overcurrent protection, and the service panel in the garage
only holds 6 switches so it doesn't need a disconnect.
If I ever do have to run telephone or gas or CATV to the garage, I'll bury
it, and I'll redo the 60A feeder with four #6 wires in a 1" rigid conduit
in the same trench.
That makes the remote system like a service in and of itself, requiring
a ground rod.
Again, I install a 4 wire feed, so one of the wires is an earth safety
conductor (green), and not carrying a load.
I figure at worst, the inspector would require a derating to 50 amps
Use Quadplex and tie the messenger to the old service mast with a lug or
grounding clamp. The Aluminum Clad Steel Reinforced (ACSR) messenger
cable that supports the other three conductors of the quadplex then
serves as the Equipment Grounding Conductor (EGC). If the original
service mast for your home is discontinuous between the panel and the
service head then you will have to bond around any gaps.
Remember that you have to build a Grounding Electrode System at the
detached garage consisting of a minimum of two eight foot ground rods
spaced at least six feet apart.
The grounded conductor in the old service entrance is not insulated, so I
don't think I can use it for a neutral and the old service mast as a ground
-- so I can't tell if the raceway is continuous back to the service panel
or not because the grounded conductor inside will be shorted to the
raceway. I'm gonna attach the messenger wire of the 3plex to the bare
conductor and the insulated wires to the old insulated wires (obviously)
and the messenger wire will be my neutral *and* my equipment ground.
Two electrodes? I thought I only needed one 5/8" x 8' ground rod for a 60A
feeder to a separate building. (I think I'll ask the inspector if I need a
second electrode before I buy the grounding wire, in case I need an
unspliced conductor long enough to reach both ground rods.) Is this a new
rule? When I wired my old garage 10 years ago using the exact same method
I only used one electrode and the inspector thought it was just fine.
Hey, I just thought of something. Maybe I can use 4plex and attach the
messenger wire to the grounded service entrance conductor of the *new*
house service. It might look kind of weird, but I think the grounded
service entrance conductor or the service entrance raceway can be used as
an equipment ground. The old service mast and the new one are about 18
inches apart, and there's a big insulator right between the two for the
messenger wire for the garage to clamp onto. I think I need to dig up my
code book and study it before I ask the inspector any stupid questions.
Your best approach is to use the existing raceway and repull it using an
insulated #6 THWN neutral. The code allows up to five compact stranded
THWN conductors in a 3/4" rigid conduit so you could even add a bare
stranded number eight equipment grounding conductor to the raceway if
you wanted to. You may not tie any of the conductors to the garage into
the service entrance wires because that connection would be on the
utility side of the service disconnecting means and because the US NEC
requires that all conductors of a circuit be in the same raceway or cable.
As for the grounding electrode system the code language has changed so
that if the first rod does not have an impedance of 25 ohms or less a
second rod is required. Since the equipment to measure the impedance of
grounding electrodes cost 1000 dollars and up most of us just install
two rods and let it eat. The Grounding Electrode Conductor does need to
be continuous between electrodes (rods) but it does not have to be
continuous from the second rod all the way back to the service
disconnecting means. Since the acorn clamps are only listed to
terminate a single conductor it is easier to keep the conductor
AFAIK, a cheap and easy way to test a ground system, is that it should
be able to light up a 100w bulb when connected between hot and ground.
If the ground resistance is too high, the bulb won't light up fully. I
may be wrong on the bulb size (maybe a 60w?), but the idea behind the
test is valid.
If you can get the inspector to accept your field expedient test than
more power to you. I test my grounds as a matter of course and I rarely
get less than twenty five ohms with two rods let alone just one. I have
driven sectional rods to depths of twenty five feet without getting less
than twenty five ohms. Your light bulb test will test the total
impedance of the earth return pathway but that does not tell you
anything specific about the impedance of the rod in question. The
assumption that the impedance of the Multi Grounded Neutral (MGN) of the
power company's distribution network is effectively zero may or may not
be acceptable to the inspector.
As far as what bulb size an impedance of twenty five ohms with a voltage
of 120 would produce a current of 4.8 amps. 4.8 amps times 120 volts is
476 watts of power. That is a heck of a lot more than one light bulb.
If you can flow enough current through the ground rod to open a five
ampere fuse than the total impedance of the circuit is less than twenty
four ohms so I guess that the demonstration of the ground rods ability
to blow a five ampere fuse would prove an impedance of less than twenty
five ohms. That does not mean that test will be acceptable to the
inspector. In general it is simpler to drive two rods and be done with
it but I never claimed that it is best practice.
I don't know if meets code, this wasn't an inspected job, I was helping
the home owner, who bought the wire. <G>
In this case, it isn't a conductor, but rather tieing the ground stake
driven in by the main box, to the water service piping, into a unified
ground, above and beyond the EMT that connects the two panels.
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