Bevis
Well-known member
Did a search earlier, but not really finding my answer. How many outlets, can I put on a circuit, with a 20amp breaker ? The wire should be 12-3 correct ?
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how many outlets / circuit??
- Thread starter Bevis
- Start date
You can put as many outlets as you want on a circuit. However, you will want to figure in what you are planning on using the outlets for to decide how many circuits to use. As far as the wire goes, 12/2 with ground is what you will need.
rickairmedic
Well-known member
I am prety sure the NEC says 8 outlets per circuit and you can use 12/2 with ground on a 20 amp circuit as was stated above.
Rick
Rick
Steve in Mi
Well-known member
Did a search earlier, but not really finding my answer. How many outlets, can I put on a circuit, with a 20amp breaker ? The wire should be 12-3 correct ?
I have 4 - 6 outlets per ckt. however they are physically located (separated) such that it would be impossible for me to be using more than one outlet on a given ckt. at the same time. 12 -2 w/g for 120 volt outlets and 12 -3 w/g for 240 volt outlets on 20 Amp, single and 2 pole breakers respectively.
I am prety sure the NEC says 8 outlets per circuit and you can use 12/2 with ground on a 20 amp circuit as was stated above.
Rick
Chapter and verse please.
There is nothing in the NEC that limits the number of outlets per circuit.
D KRAGER
Well-known member
Just try to separate things that may run at the same time, put them on separate circuits.
rcleaver
Well-known member
Remember too, that you're less likely to have a problem with tripping breakers with a 20 amp circuit. I've run a 3 hp router, CNC machine and dust collector on the same circuit at once with no problems. I just start them one at a time.
nissan_crawler
Well-known member
I prefer to keep circuits as separated as possible. I only have a 20x24 garage, and have almost all spaces used in a 20 slot panel.
Basically, I would separate them as much as possible, while leaving a few empty slots in the panel for a future circuit.
Also, you can never have too many outlets. I have 4-240 volt outlets, 2-4 plug 120 boxes, 2-3' outlet strips, and 7-2plug 120 boxes. They all get used quite frequently.
Basically, I would separate them as much as possible, while leaving a few empty slots in the panel for a future circuit.
Also, you can never have too many outlets. I have 4-240 volt outlets, 2-4 plug 120 boxes, 2-3' outlet strips, and 7-2plug 120 boxes. They all get used quite frequently.
nissan_crawler
Well-known member
Chapter and verse please.
There is nothing in the NEC that limits the number of outlets per circuit.
I know what you mean, and for a garage, that's usually right. However, depending on what's plugged into the circuit, there is a limit. In 99% of cases it wouldn't apply for garage, though.
Aceman
Well-known member
Did a search earlier, but not really finding my answer. How many outlets, can I put on a circuit, with a 20amp breaker ? The wire should be 12-3 correct ?
Check with your inspector, many cities have amended the NEC to limit the amount of receps per circuit.
Or, you can look at how many tools you'll have running multiplied by the amount of people working at the same time and go from there.
kutza
Well-known member
I recently started looking into the same electrical topics, and wanted to share the link i found with lots of new knowledge, ( i know nothing about electrical work).
http://www.selfhelpandmore.com/home-wiring-usa/accessory-structures-to-dwellings/wiring-a-detached-garage-2002.php
http://www.selfhelpandmore.com/home-wiring-usa/accessory-structures-to-dwellings/wiring-a-detached-garage-2002.php
Charles (in GA)
Well-known member
NEC 220.10 discusses branch circuit load calculations. For the number of receptacles on a single branch circuit, 220.14(L) is probably the best reference, requiring that you use 180 volt/amperes per outlet as a means of calculating this. An outlet would be a "strap" thus a single receptacle or a common duplex receptacle would be treated at the same 180 VA.
This works out to 180VA divided by 120 volts equals 1.5 amps per strap.
20 amp breaker divided by 1.5 amps equals 13.3 or 13 straps or outlets (receptacles)
Thats 10 receptacles on a 15 amp breaker.
As already noted, local inspectors may have different ways of figuring this, or different requirements, so your mileage may vary.....
Charles
This works out to 180VA divided by 120 volts equals 1.5 amps per strap.
20 amp breaker divided by 1.5 amps equals 13.3 or 13 straps or outlets (receptacles)
Thats 10 receptacles on a 15 amp breaker.
As already noted, local inspectors may have different ways of figuring this, or different requirements, so your mileage may vary.....
Charles
Last edited:
JOHNMAN
Well-known member
So in a garage in general, (in the USA), it is required to have GFCI protection on all 110 VAC circuits that are not hard wired?
I think I saw something like that before reading the selfhelp link posted above.
Can anyone other than the local building inspector really answer this?
I know that the detached building that is included with the property that I am buying is already built and occupied (and all circuits out there are not GFCI).
Only the "normal" outlets around water or outside are protected this way.
I don't intend to use GFCI breakers and I hate the outlets, but I could always put one GFCI outlet at the beginning of each branch run to be in compliance.
What are the typical rules regarding installing a 3-way switch in one structure that gets power from a separate structure? (i.e. a 3-way switch in the house that turns on outside lighting on the detached building and power comes from the detached building)? Are there special colors to be used? Any tags or labels required?
I think I saw something like that before reading the selfhelp link posted above.
Can anyone other than the local building inspector really answer this?
I know that the detached building that is included with the property that I am buying is already built and occupied (and all circuits out there are not GFCI).
Only the "normal" outlets around water or outside are protected this way.
I don't intend to use GFCI breakers and I hate the outlets, but I could always put one GFCI outlet at the beginning of each branch run to be in compliance.
What are the typical rules regarding installing a 3-way switch in one structure that gets power from a separate structure? (i.e. a 3-way switch in the house that turns on outside lighting on the detached building and power comes from the detached building)? Are there special colors to be used? Any tags or labels required?
hidollartoys
Well-known member
NEC 220.10 discusses branch circuit load calculations. For the number of receptacles on a single branch circuit, 220.14(L) is probably the best reference, requiring that you use 180 volt/amperes per outlet as a means of calculating this. An outlet would be a "strap" thus a single receptacle or a common duplex receptacle would be treated at the same 180 VA.
This works out to 180VA divided by 120 volts equals 1.5 amps per strap.
20 amp breaker divided by 1.5 amps equals 13.3 or 13 straps or outlets (receptacles)
Thats 10 receptacles on a 15 amp breaker.
As already noted, local inspectors may have different ways of figuring this, or different requirements, so your mileage may vary.....
Charles
I agree with the interpertation. However I believe that you should also figure a 80% max load on a branch curcuit. This allows some safety factor for preventing breaker trip. This is how I figure the quanity of "loads" on a circuit when I do remodeling. I dont want to get called by the home owner that the breaker keeps tripping.
Charles (in GA)
Well-known member
So in a garage in general, (in the USA), it is required to have GFCI protection on all 110 VAC circuits that are not hard wired?
I think I saw something like that before reading the selfhelp link posted above.
Can anyone other than the local building inspector really answer this?
I know that the detached building that is included with the property that I am buying is already built and occupied (and all circuits out there are not GFCI).
Only the "normal" outlets around water or outside are protected this way.
I don't intend to use GFCI breakers and I hate the outlets, but I could always put one GFCI outlet at the beginning of each branch run to be in compliance.
This depends on which code the building was wired to. Not sure when the GFCI requirement came into effect, but if it was wired prior to that code, then it is quite legal. Its also possible that some building inspectors might allow some leeway on this requirement, so there are reasons why the building might not have GFCI protection.
Charles
nissan_crawler
Well-known member
If I could get by without gfci, I would. I installed one for pressure washer/cord in lawn type use, but that's it. Otherwise, it's a PITA in a garage.
bofus
Well-known member
In my shop, I have several 20 amp circuits with 12 duplex outlets on each with a 20 amp rated GFCI at the first postion and used 12-2. Passed inspection.
CalGeo
Active member
NEC 220.10 discusses branch circuit load calculations. For the number of receptacles on a single branch circuit, 220.14(L) is probably the best reference, requiring that you use 180 volt/amperes per outlet as a means of calculating this. An outlet would be a "strap" thus a single receptacle or a common duplex receptacle would be treated at the same 180 VA.
This works out to 180VA divided by 120 volts equals 1.5 amps per strap.
20 amp breaker divided by 1.5 amps equals 13.3 or 13 straps or outlets (receptacles)
Thats 10 receptacles on a 15 amp breaker.
As already noted, local inspectors may have different ways of figuring this, or different requirements, so your mileage may vary.....
Charles
Charles is correct again, plus the 80% factor. I run a 12/3 in the garage or shop to five locations and use a four plex (two duplex receptacles) at each location. This gives me two circuits at each locations in case I want to run two power tools at one time without worrying that I will trip a breaker. You can also run the 12/3 in and out of the single duplex box alternating the two circuits. Remember to tie the two breakers together too.
Most people don't have a real concern about tripping a breaker because of their shop use. IMO, it is best to keep the amount of receptacles to four or five per circuit in a multi person shop.
Torque1st
MEMBER EMERITUS
I always physically plan out my outlets so I only have one wall's outlets on each circuit. That is all the north wall outlets on a circuit either 110 or 220, all the east wall circuits on a circuit... Plus dedicated circuits for various shop tools etc. This works for normal 2-3 car size garages or shops. When you get to big places it does not.
When you buy a breaker panel get the big 40 size panels, they only run a few $ more than the 30 breaker panels.
When you buy a breaker panel get the big 40 size panels, they only run a few $ more than the 30 breaker panels.
I know what you mean, and for a garage, that's usually right. However, depending on what's plugged into the circuit, there is a limit. In 99% of cases it wouldn't apply for garage, though.
I mentioned that in my first post; you need to plan ahead for what is being used.
NEC 220.10 discusses branch circuit load calculations. For the number of receptacles on a single branch circuit, 220.14(L) is probably the best reference, requiring that you use 180 volt/amperes per outlet as a means of calculating this. An outlet would be a "strap" thus a single receptacle or a common duplex receptacle would be treated at the same 180 VA.
This works out to 180VA divided by 120 volts equals 1.5 amps per strap.
20 amp breaker divided by 1.5 amps equals 13.3 or 13 straps or outlets (receptacles)
Thats 10 receptacles on a 15 amp breaker.
As already noted, local inspectors may have different ways of figuring this, or different requirements, so your mileage may vary.....
Charles
220.14 is in regards to fixed multioutlet assemblies, not a general purpose receptacle, however it is a good number to go off of. For someone's personal garage or home, the best bet is to decide ahead of time what you are going to be using the outlets for and space them and add circuits according to the future use.
BTW, you should only plan on using 80% of the circuit for a safety margin, so that would give you 10 outlets using the 180VA on a 20amp circuit.
there i some good information here. I'll mainly be the only person in my shop running any power tools, unless a friend stops by. I'm trying to place outlets where I think that I might need them, or where I'm gonna have my power tools, and other electric needs. So with the 10 outlets per circuit, I can get away with about two maybe three circuits.
wayoff
Well-known member
There is no limit because the amount of current you can draw through a 10/2 wire is more than what the 20 amp breaker will handle. So the worst that can happen if you have too many things plugged in is you'll pop the breaker way before the wire can heat up. So it gets down to common sense. You'll find in most garage applications that people run 6-8 on a 20 amp breaker, but in a residential it is not uncommon to see people run up to 12 on a 15 amp.
Question
Well-known member
The only thing that the inspector tested in my garage was the GFI's, then went to each box and tripped the GFI. I asked how many more boxes I could add, he said as many as I want as long as they were GFI protected...
sberry
Banned
I got a bunch of them, single breaker to single duplex and left a lot of things so I could wire as I went. When I figured out what went where it got its own circuit, especially heavy draw items or hard motor starts.