Looks Like my 200 amp Main is Full ... adding a Sub Panel ...

[Tim_in_NC]

Hi Guys ...

I'm new here and have decided to begin a somewhat small garage renovation so that it feels more like a small shop, and to be able to fit another vette in the garage as well ... with the help of a bendpak lift ...

So, I wanted to start off by adding more electrical outlets/drops in the garage which currently only has 1 electrical outlet ...

I'd like to add about 6-8 (110V) or so outlets around the garage (Used for Refrigerator, 1.6HP compressor, various power tools, neon lights, tv, stereo, bendpak lift, in-window A/C unit, etc...) and then 1 (220V) that I may use for a welder or other gear that demands a 220 ...

Our home came with a 200A Main with 30 circuits but every slot was taken by the original electrician ...

I'd like to add a 100A sub panel and install it in the garage, the mounting location will only be about 6 feet away from the main ...

I plan to wire all the outlets, install the sub panel in the garage, but will most likely have an electrician come in a run the power from the main to the sub, unless I feel that it's definitely too easy for me to pass up ...

So, after looking at the pics that I've added, what do you think is the best way to get power from the main to the sub panel?

Can I simply remove 4 of the 15amp breakers and install 2 tandem 15 amp breaker to replace the 4 that were removed and then install a 100 amp, double pole circuit in the available slot?

Thanks,
TIM

 

[pl_silverado]

I guess the easiest would be to replace two breakers on either side with tandem breakers, which would free up enough slots for a double pole 100amp to feed your sub panel.

If you think thats bad, you should see mine. I have a siemens 200amp panel, with 100 amp sub panel, and between the two of them, only 4 free slots........and thats just for the house. Apparently the sparky who rewired it thought every single thing needed its own circuit.

You may want to clamp an amp meter on the incoming service when your a/c & what not is running to see how much of that 200 amp service is in use, to see whether you'll even be able to add any additional loads.

 

[Charles (in GA)]

That panel only has 30 slots in it. I'll bet its a 30/40 panel. If you look at the info on the door it probably says you can put tandem breakers in the bottom five slots on each side (adding ten breakers, bringing the total up to 40)

In fact, I'm sure it is. Look at the placard, the place where you write what the circuit is for, slots 21 and 22 and below have a dotted line across them, indicating the possibility of two circuits, while slots 19 and 20 and up do not have those dotted lines. You CANNOT install tandem breakers in slots 1 thru 20 but CAN install them in slots 21 thru 30.

Again, check the door placard for info on the max number of circuits allowed.

Charles

 

[mrb]

whats the load youre adding with the garage? Outlets and lights or Big compressor and plasma cutter? 200 amps minus all that electric heat and hwh, plus normal hosue loads and you may not have a ton of capacity left.

 

[pattenp]

You may have a couple of those circuits than can be moved to the new sub panel.

 

[Tim_in_NC]

That panel only has 30 slots in it. I'll bet its a 30/40 panel. If you look at the info on the door it probably says you can put tandem breakers in the bottom five slots on each side (adding ten breakers, bringing the total up to 40)

In fact, I'm sure it is. Look at the placard, the place where you write what the circuit is for, slots 21 and 22 and below have a dotted line across them, indicating the possibility of two circuits, while slots 19 and 20 and up do not have those dotted lines. You CANNOT install tandem breakers in slots 1 thru 20 but CAN install them in slots 21 thru 30.

Again, check the door placard for info on the max number of circuits allowed.

Charles

You're correct, slots 21-30 will accommodate tandems ... the other will not

 

[mrb]

You may have a couple of those circuits than can be moved to the new sub panel.

why? too much trouble. reuse the removed breakers in the new subpanel and your net cost for the two tandems needed is ~$12, no work other than swapping the breakers, and you have the 2 needed empty spaces.

 

[Tim_in_NC]

whats the load youre adding with the garage? Outlets and lights or Big compressor and plasma cutter? 200 amps minus all that electric heat and hwh, plus normal hosue loads and you may not have a ton of capacity left.

3 or 4 neon lights, refrigerator, bendpak HD-9 lift, 1.6hp craftsman compressor, tv, radio, a few power tools ... and a 220 for a welder down the road ... Not all will be running together ...

 

[Tim_in_NC]

Sounds like 2 tandems and a 100a double is the way to go ... correct ...

 

[Aceman]

How big is that hood fan? They don't usually draw much, I might be inclined to combine circuit 17 & 21. Then use one tandem for the washer and garage door opener. That'd free up spaces 21 & 23.

Buy some #2 SER, put it on an 80 amp breaker to feed a main lug panel, I'd say at least 12 spaces or so and you should be set.

 

[Tim_in_NC]

How big is that hood fan? They don't usually draw much, I might be inclined to combine circuit 17 & 21. Then use one tandem for the washer and garage door opener. That'd free up spaces 21 & 23.

Buy some #2 SER, put it on an 80 amp breaker to feed a main lug panel, I'd say at least 12 spaces or so and you should be set.

Why would you use choose an 80amp over a 100amp?

 

[Aceman]

Because #2 SER is readily available. If you held the 1/0 SER in your hand that you needed to use to get the full 100 amps, I bet you'd understand.

That, and the fact I don't think you need a FULL 100 amps for what you're doing.

 

[gatchel]

Why would you use choose an 80amp over a 100amp?

No he didn't

 

[Tim_in_NC]

Because #2 SER is readily available. If you held the 1/0 SER in your hand that you needed to use to get the full 100 amps, I bet you'd understand.

That, and the fact I don't think you need a FULL 100 amps for what you're doing.

Thank you for the explanation ... So, I should be set with 2 tandems to combine 4 slots into 2, and a double 80a breaker for the open slot to feed the sub panel ... then use #2 Service Entrance Cable for the connection ... If we were ever interested in added a hot tub, would it be better to go with the 100a option?

When running the outlets in the garage for general usage and small power tools ... do most use a 20a breaker for every 2, 110v electrical outlets? Was thinking of running the compressor & lift off of it's own breaker, I need to check their amperage ...

 

[pattenp]

why? too much trouble. reuse the removed breakers in the new subpanel and your net cost for the two tandems needed is ~$12, no work other than swapping the breakers, and you have the 2 needed empty spaces.

I was just giving another option. I didn't say it was the best one.

 

[pattenp]

When running the outlets in the garage for general usage and small power tools ... do most use a 20a breaker for every 2, 110v electrical outlets? Was thinking of running the compressor & lift off of it's own breaker, I need to check their amperage ...

All depends on the load that you are going to have on the outlets as to how many you have on a circuit. In most cases you can do more that two. In my garage I put 5 outlets on each 20A circuit. As far as the lift and compressor go they should be on their own separate circuits if they are 240v.

 

[theoldwizard1]

If you are going to put more than 1 circuit for receptacles (I assume a separate circuit for lights) and have multiple receptacles running the length of the wall(s), put every other receptacle on the opposite circuit. Less chance of an overload when using multiple power tools simultaneously like a saw and a vacuum and it is easy to remember ! (That is the way load center back planes are arranged.)

Other than the case I just mentioned, if you have your compressor and lift pump motor on a separate circuit, you almost don't need 2 - 20A circuits in a typical "home" workshop.

PS. Don't forget to buy 20A rated receptacles and to use a 20A GFCI receptacle for the first one in the string !

PPS. The hot tub I took out was on a 50A breaker.

 

[mrb]

Why 20A receptacles? Do you have equipment with 20A plugs on it? Same goes for GFCI. All 15 amp receptacles can be used on 20 amp circuits unless its a single (not a duplex) receptacle and you only have one on the circuit.

 

[theoldwizard1]

Why 20A receptacles? Do you have equipment with 20A plugs on it? Same goes for GFCI. All 15 amp receptacles can be used on 20 amp circuits unless its a single (not a duplex) receptacle and you only have one on the circuit.

Why not ?

I know 120V 20A equipment is not common, but I would feel more comfortable plugging a high current, 120V power tool (compressor) into a 20A receptacle than into a 15A one.

Also I don't think any one makes cheap, "residential", 120V 20A receptacles.

 

[Tim_in_NC]

PS. Don't forget to buy 20A rated receptacles and to use a 20A GFCI receptacle for the first one in the string !

PPS. The hot tub I took out was on a 50A breaker.

Wizard ... Here is a drawing that I found online ... when grouping outlets to the same breaker, do I make the 1st outlet a GFCI or all outlets, except for the last one in the chain, GFCI and attach the last one as shown in the pic so that it's fully protected?

 

[pattenp]

You can hook the GFCI outlets in different ways. You can put it first in the circuit and wire the rest of the circuit off the load side making all outlets protected off the one GFCI. You can use a GFCI for every every outlet if you want. Some people like every outlet to be a GFCI because it's easier to locate a fault when one trips vs. having one GFCI protecting multiple outlets down stream. The picture you posted is just an example of one of many ways.

 

[Tim_in_NC]

You can hook the GFCI outlets in different ways. You can put it first in the circuit and wire the rest of the circuit off the load side making all outlets protected off the one GFCI. You can use a GFCI for every every outlet if you want. Some people like every outlet to be a GFCI because it's easier to locate a fault when one trips vs. having one GFCI protecting multiple outlets down stream. The picture you posted is just an example of one of many ways.

Perfect ... thank you

 

[mrb]

Why not ?

I know 120V 20A equipment is not common, but I would feel more comfortable plugging a high current, 120V power tool (compressor) into a 20A receptacle than into a 15A one.

Also I don't think any one makes cheap, "residential", 120V 20A receptacles.

the inside of a 20a receptacle is the same as a 15a receptacle of a given model / series. The current carrying parts are all the same. if you want to avoid crappy receptacles you dont have to do so by using 20 amp -just buy good receptacles.

 

[Milton Shaw]

I would sure use 12-2wg instead of that 14/2 he is showing in the post with wiring diagrams. 14-2 is adequate for lights but would not use it for any outlets. Make sure you put outlets high enough to be over benches and other items. Yes you need 20 amp circuits in the shop, I have some 120volt saws that pull 13 amps by themselves. Cannot run them on outlet strips they kick their 10 amp breaker.

 

[Tim_in_NC]

Ok ...

I've put together a few, simple drawings that illustrate what I'm wanting to accomplish with my garage, both via aesthetics and electrical ...

Cliff Notes:

7 Separate Breakers in the Sub Panel
[1] - 20a breaker to power 3 Neon Sings & 32" LCD TV (2 outlets)
[2] - 20a breaker to power work bench lighting, various small power tools, etc... (4 outlets)
[3] - 20a breaker to solely power 33 gal. 1.6 hp Craftsman Air Compressor (1 outlet) ... may need 30 amp will double check ...
[4] - 20a breaker to power Refrigerator/Freezer Combo (1 outlet)
[5] - 15a breaker to power small stand up grinder/buffer, etc... (2 outlets)
[6] - 30a breaker to power Lincoln Electric Pro-Mig 140 (1 outlet)
[7] - 30a breaker (220v) to power Bendpak HD-9 via overhead drop (1 outlet)

Am I over killing anything here or on the right path?

Which of these 2 panels should I use as my Sub Panel in the Garage:

Panel A - Square D 24-Circuit 12-Space 125-Amp Main Lug Load Center

Panel B: Square D 24-Circuit 24-Space 100-Amp Main Breaker Load Center

OR should I be looking at a different Panel for the Sub?

Here's a link to the Compressor & the Welder ... I'm hoping 20a and 30a respectively will be sufficient ... but may need 30 on the compressor ...

Next I need to spec out all the romex ... I've got 14/2 for 15a and 12/2 for 20a ... Is it 10/2 for the 30a 110v and 10/3 for the 30a 220v drops?

 

[pattenp]

You should make that one 15A a 20A. After all those 20's why'd you skimp on the one 15A? I'd do 20A on all the 120V outlets

 

[Charles (in GA)]

What do you need 30 amp 120v for?

For 240v 30 amp you use either 10/2 w/grd if you only need the two hots and a ground, or if it is supplying something like a dryer that needs 120v inside of it for the timer, motor, etc., then you use 10/3 w/grd. So it depends on what you are supplying as to whether you use 10/2 or 10/3. Anymore, I use three wire and if I don't need the neutral, I cap it and fold it back, but its there if I need it.

Charles

 

[Tim_in_NC]

You should make that one 15A a 20A. After all those 20's why'd you skimp on the one 15A? I'd do 20A on all the 120V outlets

I was going to have an extra 15a from the Main Box so thought that I'd use it there ... ... But I should probably go ahead and go with a 20 since I'll have the Romex for it already ...

 

[Tim_in_NC]

What do you need 30 amp 120v for?

For 240v 30 amp you use either 10/2 w/grd if you only need the two hots and a ground, or if it is supplying something like a dryer that needs 120v inside of it for the timer, motor, etc., then you use 10/3 w/grd. So it depends on what you are supplying as to whether you use 10/2 or 10/3. Anymore, I use three wire and if I don't need the neutral, I cap it and fold it back, but its there if I need it.

Charles

I was planning on using the 30a 120v for this welder > Lincoln Electric Pro Mig 140

The 30a 220V is for the Electric Motor on the Bendpak HD-9 Lift

I'm going to verify that a 20a 120v will be sufficient for my Air Compressor ...EDIT ... I just checked my compressor and it states 15a so 20a should do the job ...

 

[volleyball]

I disagree on going with all 20A. For the tv and the fridge, 15A should suffice. And it is easier to pull. Light should be on their own circuit with no outlets. You don't want a drill to kill your lights. Also usually a 15A.

I would go with the 24 space panel. 100A is the max I would normally go due to costs. a 150 or 200 breaker is expensive. Also the 24 panel will be less costly than buying tandem breakers.

Actually I would plan on a bigger main panel as you are expected to have open spaces available. Maybe a QO140M200.

 

[Sureshot]

Would you not want these circuits to be 15 Amp to protect the likes of a 13 Amp saw? Will it be smoking by the time it kicks the 20 Amp breaker? I have all 15 amp with staggered outlets/breakers and run 7" grinders, 10" bench grinder, etc and would like to kick the breaker as a warning of trouble before ruining a tool. Or am I off here??

 

[mrb]

Would you not want these circuits to be 15 Amp to protect the likes of a 13 Amp saw? Will it be smoking by the time it kicks the 20 Amp breaker? I have all 15 amp with staggered outlets/breakers and run 7" grinders, 10" bench grinder, etc and would like to kick the breaker as a warning of trouble before ruining a tool. Or am I off here??

youre off. the breaker is to protect your branch circuit wiring not your appliance.

 

[rabidsquirrel]

I'm curious about the conduit at the bottom shoved full of romex.

 

[54FordPanel]

Wizard ... Here is a drawing that I found online ... when grouping outlets to the same breaker, do I make the 1st outlet a GFCI or all outlets, except for the last one in the chain, GFCI and attach the last one as shown in the pic so that it's fully protected?

Can somebody explain why are the 2nd and 3rd outlets GFIs, and the 4th one is a regular one? Why not just wire up the 1st GFI, and make all the rest regular outlets wired to the load side of the GFI?

 

[fefarms]

Can somebody explain why are the 2nd and 3rd outlets GFIs, and the 4th one is a regular one? Why not just wire up the 1st GFI, and make all the rest regular outlets wired to the load side of the GFI?

It's just an example of one code legal way to do it. It is kind of a goofy one, maybe chosen to illustrate both ways of providing GFCI protection to a receptacle.

It would be more typical to make only the first receptacle a GFCI, with the rest normal receptacles connected to the "load" terminals of the GFCI.

The next most common way to do it is to make them all GFCIs.

The example given "works" and might make sense in an environment where the last GFCI is close to the one slaved non-GFCI receptacle.

 

[kenfath]

Instead of using individual GFCI receptacles consider using GFCI breakers. Why? Cost. GCFI receptacles ~$18, GFCI circuit breaker ~$36.

??? for the NEC experts. Can you have just a single (duplex) receptacle on a 20 AMP circuit? ("I thought" a single had to be on a 15 AMP breaker.)

Having some of the wall receptacles at ~50" above the floor is good advice for the walls where you may rest 4x8' sheets or above a workbench, and perhaps where the wall has shelves. On the other hand, there is an advantage to having some closer to the floor especially for cords that will resting on the floor, or higher for TV or Liftmaster garage door opener.

Ceiling receptacles are very useful, make sure one is near the garage door opener. Now is the time to provide an outside receptacle.

Use the tamper resistant receptacles. Besides being specified in current codes they seem to work as well as the old style.

Your off to a great start! Keep us advised of your progress.

 

[Stuart in MN]

Instead of using individual GFCI receptacles consider using GFCI breakers. Why? Cost. GCFI receptacles ~$18, GFCI circuit breaker ~$36.

??? for the NEC experts. Can you have just a single (duplex) receptacle on a 20 AMP circuit? ("I thought" a single had to be on a 15 AMP breaker.)

Since a typical GFCI receptacle has feedthrough capabilities, it can protect all the other regular receptacles downstream from it. In that case it's less expensive than using the GFCI breaker. On the other hand, if the downstream receptacles are spread out across a wide area, it can be more convenient to use the GFCI breaker since it will be easier to reach in a central location. There's no single right answer, it just depends on the situation and your personal preference.

The NEC allows 15 amp receptacles on a 20 amp circuit as long as there are two or more of them. A standard duplex receptacle counts as two.

 

[mrb]

i dont know why everyone thinks using GFCI breaker is so great. The more wire on the load side of a GFCI and the more stuff connected to the load side of a GFCI the easier it will trip. Best practice is to get the GFCI as close to the load as practical.

 

[Charles (in GA)]

??? for the NEC experts. Can you have just a single (duplex) receptacle on a 20 AMP circuit? ("I thought" a single had to be on a 15 AMP breaker.)

A duplex receptacle (common electric wall receptacle) is considered TWO receptacles by the code and you are allowed to have just one 15 amp duplex receptacle on a 20 amp breaker.

You cannot have a 15 amp single receptacle on a 20 amp breaker, if this is the only receptacle on the circuit.

NEC 210.21(B)(3)

Charles

 

[jake26]

A duplex receptacle (common electric wall receptacle) is considered TWO receptacles by the code and you are allowed to have just one 15 amp duplex receptacle on a 20 amp breaker.

You cannot have a 15 amp single receptacle on a 20 amp breaker, if this is the only receptacle on the circuit.

NEC 210.21(B)(3)

Charles

To understand what you are saying, as long as you have multiple 15 amp duplex receptacles on a circuit, you can use a 20 amp breaker?