Hey I was curious I have a building without power. It is already wired with a receptacle and light. I would like to run power out to the building and add a new circuit to my breaker box. I know enough about electrical to get in trouble, I would most certainly pull a permit to get it inspected. Is this something you would feel comfortable doing as a weekend warrior?
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Running Power to a building
- Thread starter faipmafia
- Start date
dcg9381
Well-known member
Many of us do this sort of thing as "weekend warriors"... Personally, I can't tell you if you are qualified to do it - nor can I indicate that I'm qualified to do it half the time. What I can tell you is that this forum is very helpful.
There's not a huge difference in running a circuit to a sub-panel for a building compared to installing a 120V circuit with a breaker. That being said, in some areas you're not allowed to this at all unless you have a license. And in others, there is no inspection or any other oversight that says you can't do it yourself.
Remember than when bringing power into a building - the type of power line matters - all sorts of things. If you've got a plan, post it up and let some of the guys who are qualified shoot holes in it to help you.
There's not a huge difference in running a circuit to a sub-panel for a building compared to installing a 120V circuit with a breaker. That being said, in some areas you're not allowed to this at all unless you have a license. And in others, there is no inspection or any other oversight that says you can't do it yourself.
Remember than when bringing power into a building - the type of power line matters - all sorts of things. If you've got a plan, post it up and let some of the guys who are qualified shoot holes in it to help you.
Bretny
Well-known member
The real question is weather YOU feel comfortable doing it. Not if i feel comfortable. I already ran my own 100a service to my garage. When i say i i dont mean i hired any part of it out.
Kevin Essiambre
Well-known member
Is this something you would feel comfortable doing as a weekend warrior?
Something I would feel comfortable doing? Yes. But I do this for a living. You should be asking yourself if you are comfortable doing this. There are quite a few people on this forum that have taken on a project like this. But of you don't feel comfortable doing it, I would suggest hiring someone to do this for you.
As others have said, there are areas that require a licenced electrician and other areas where they might not even require a permit. I would start there, and check to see if it's something you're permitted to do in your area.
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Terry D
Well-known member
As others have mentioned, check your local codes. Sometimes they offer a homeowner permit so you can do it your self. Its usually a small test with basic electrical questions. If you cant pass the test, then I would not try it myself until I got more familiar with it. Maybe your area doesn't even require permits. Are you going underground or overhead. Each of these installations has its own requirements. Electric is probably something you shouldn't do if you only know enough about it to get in trouble.
AntonLargiader
Well-known member
Sounds like you want to run a branch circuit out to the building, which is pretty simple as long as you can install the wire. It's simpler than installing a subpanel. Here's part of something I wrote up some time ago, regarding that. Although there may be some errors, it's probably a good starting point:
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For small demands, like a few lights and receptacles, you may run a branch circuit from your house panel. The NEC prohibits multiple feeds to a structure, so only one such circuit is allowed, but a multi-wire branch circuit (MWBC, two hots and a shared neutral) counts as a single circuit for this purpose. For garages, it must be a MWBC because the required 20A receptacle(s) cannot be on the same circuit as the lights.
Advantages: you do not have to install a panel with separate grounding. Running a single circuit to a garage is almost like running a single circuit to an outdoor lamppost. Also, you might avoid the need for a permit and inspection.
Disadvantage: For a garage, you are limited to two 120V/20A circuits because one leg must be receptacles only. For a building other than a garage, it's possible to go larger and fuse the circuits separately, or connect a 240V outlet, but you might as well have a subpanel at that point.
Note: There is no limit to the number of receptacles on a circuit, but the lighting circuit must support all of the fixtures at their maximum rated wattage (220.14 D). Example: 20A circuit x 120V = 2400W. Since lighting is considered a continuous load, this is derated to 80%, or 1920W. Your total light fixture maximum wattage ratings (even if you have LED bulbs in them drawing 5% of max) cannot exceed 1920W.
Requirements:
You must have a means of disconnect at the point of entry (a 15A snap switch is OK for each leg). This means the receptacles must be switched. The switches have to be the first things in the circuits so that they disconnect everything. They must be 2-pole switches, as 3-way or 4-way switches do not de-energize the rest of the circuit. (225.39)
The MWBC must be fed from a dual breaker or handle-tied pair.
Note: use a handle-tied pair to keep power to one leg when the other trips, a dual breaker to shut both legs off in the event of a trip. If you are using 240V from both legs (in something other than a garage, where it isn't allowed) you must have a dual breaker.
Although there are no requirements for limiting voltage loss over distance, 3% loss at max load is a typical target. For a 15A load, that means 12AWG wire will take you 69 feet. See https://www.southwire.com/support/voltage-drop-calculator.htm for your actual situation.
Typical installations use direct-buried UF-B or wet-rated (THWN, XHHW) individual strands in PVC conduit. Every means of getting power to a detached building is considered to be a wet location. UF-B will need to be in conduit where it is exposed to damage, typically from where it leaves the house down to 18", and the same at the outbuilding plus any protection required in the outbuilding. Individual strand wiring needs to be in conduit everywhere. Bury depths are detailed in table 300.5 but the basics for this type of setup usually come down to:
120V, 20A direct-bury, with GFCI breaker: 12" (not applicable to garages because it's a single branch)
Other direct-bury including MWBC: 24", 18" under driveways
In PVC conduit: 18"
You can also run it overhead, although this is less common. There are quite a few requirements for this and they are detailed in 225 Part I.
A typical install could look like this: Dual 20A breaker in panel, feeds 12-3 UF-B which is stapled to ceiling joists in unfinished basement, passes through basement wall in PVC conduit with packing at the conduit entrance, conduit extends 18" below grade, UF-B buried 24" deep out to garage, back up through conduit starting 18" below grade, PVC conduit extends up wall of shed and into back of deep 4x4 box with two 2-pole switches. From there one circuit goes to lights and one goes to receptacles (the first being GFCI, wired so as to protect the downstream receptacles).
===========
You should find out what the rules are in your particular jurisdiction, because what I wrote above is generic.
=======
For small demands, like a few lights and receptacles, you may run a branch circuit from your house panel. The NEC prohibits multiple feeds to a structure, so only one such circuit is allowed, but a multi-wire branch circuit (MWBC, two hots and a shared neutral) counts as a single circuit for this purpose. For garages, it must be a MWBC because the required 20A receptacle(s) cannot be on the same circuit as the lights.
Advantages: you do not have to install a panel with separate grounding. Running a single circuit to a garage is almost like running a single circuit to an outdoor lamppost. Also, you might avoid the need for a permit and inspection.
Disadvantage: For a garage, you are limited to two 120V/20A circuits because one leg must be receptacles only. For a building other than a garage, it's possible to go larger and fuse the circuits separately, or connect a 240V outlet, but you might as well have a subpanel at that point.
Note: There is no limit to the number of receptacles on a circuit, but the lighting circuit must support all of the fixtures at their maximum rated wattage (220.14 D). Example: 20A circuit x 120V = 2400W. Since lighting is considered a continuous load, this is derated to 80%, or 1920W. Your total light fixture maximum wattage ratings (even if you have LED bulbs in them drawing 5% of max) cannot exceed 1920W.
Requirements:
You must have a means of disconnect at the point of entry (a 15A snap switch is OK for each leg). This means the receptacles must be switched. The switches have to be the first things in the circuits so that they disconnect everything. They must be 2-pole switches, as 3-way or 4-way switches do not de-energize the rest of the circuit. (225.39)
The MWBC must be fed from a dual breaker or handle-tied pair.
Note: use a handle-tied pair to keep power to one leg when the other trips, a dual breaker to shut both legs off in the event of a trip. If you are using 240V from both legs (in something other than a garage, where it isn't allowed) you must have a dual breaker.
Although there are no requirements for limiting voltage loss over distance, 3% loss at max load is a typical target. For a 15A load, that means 12AWG wire will take you 69 feet. See https://www.southwire.com/support/voltage-drop-calculator.htm for your actual situation.
Typical installations use direct-buried UF-B or wet-rated (THWN, XHHW) individual strands in PVC conduit. Every means of getting power to a detached building is considered to be a wet location. UF-B will need to be in conduit where it is exposed to damage, typically from where it leaves the house down to 18", and the same at the outbuilding plus any protection required in the outbuilding. Individual strand wiring needs to be in conduit everywhere. Bury depths are detailed in table 300.5 but the basics for this type of setup usually come down to:
120V, 20A direct-bury, with GFCI breaker: 12" (not applicable to garages because it's a single branch)
Other direct-bury including MWBC: 24", 18" under driveways
In PVC conduit: 18"
You can also run it overhead, although this is less common. There are quite a few requirements for this and they are detailed in 225 Part I.
A typical install could look like this: Dual 20A breaker in panel, feeds 12-3 UF-B which is stapled to ceiling joists in unfinished basement, passes through basement wall in PVC conduit with packing at the conduit entrance, conduit extends 18" below grade, UF-B buried 24" deep out to garage, back up through conduit starting 18" below grade, PVC conduit extends up wall of shed and into back of deep 4x4 box with two 2-pole switches. From there one circuit goes to lights and one goes to receptacles (the first being GFCI, wired so as to protect the downstream receptacles).
===========
You should find out what the rules are in your particular jurisdiction, because what I wrote above is generic.