Where does a "branch circuit" enn?

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renosteinke

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Location
NE Arkansas
A reference to 225.30 in another thread makes me wonder a bit....

225.30 says, in essence, that a detached building can be supplied by only one source of supply. Fair enough, seems to make sense, except ... Let's look at a fairly common situation:

Imagine a house with a detached garage. Personally, I'm picturing the house I grew up in- a simple ranch-style house, with a 2-car garage set perhaps 15-ft away, slightly behind and to the side of the house- but no matter. What does matter is that there was an arrangement where lights on the face of the garage, the patio, and on the end of the house that bordered the drive were all controlled by the same switches. Flip one on, they all come on.

Now, let's compound this with a very common situation: The homeowner re-tasks the garage, to be a workshop, man cave, even separate apartment. He has a panel set, even a new service, to supply the increased needs of this garage.

Here's are the questions: Does that switch loop serving the outside lighting mean we now have a violation of 225.30? Is the switch loop a 'branch circuit?" Does bringing a neutral to each switch (as now required if you're using UF or NM) change your answer?

As I read 225.30, it appears that the NEC has now made illegal the very common, and sensible, practice of mounting lights from a common switch on different buildings.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Electrical Engineer
The switch loop is not itself a branch circuit, but it is part of one. The branch circuit starts at the breaker and ends at the farthest downstream load, even if the circuit goes out to the garage and comes closer to the breaker before hitting the farthest downstream load which happens to be on the face of the house. So yes, what you suggest would be a violation. Is it a good idea to have a three-way switch setup to turn on the lights between the house and the garage from either location? Yes. Is it a violation? Yes, if there is a separate circuit or power source serving the garage. Is it worth asking for a variance? Yes. Would a variance be granted? Who knows.
 

pete m.

Senior Member
Location
Ohio
If at all possible re-feed the lighting/switches from the garage and the violation goes away.

Pete
 

charlie b

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Location
Lockport, IL
Occupation
Electrical Engineer
I thought of that Pete. But would you lose the ability to turn on the lights that illuminate the walkway between the house and the garage, using a three way switch arrangement? My daughter had this in the house they just sold. They would park the car in the garage, turn on the outside light, walk into the house, and turn off the outside light. That was very convenient. Can it be done if the power source starts in the house, then feeds the garage, then feeds a light that is attached to the house, without bringing the same violation back into play?
 

Daja7

Senior Member
good soulution for that is a device made by Illumra. It is a wirless switch but uses no batteries. You just cinnect the relay in the sw box. (it is small enough to do that) and put one switch in the garage and one in the house in place of existing wired switch. they will work up to 150 ft feet away depending on how many walls. used them several times and they work great. the switch generates its own signal without batteries. you will need a neutral in the switch box or you can out the relay in the fixure box. check it out.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
There are exceptions to the 225.30 rule. Isn't 225.30(D) still there? This allows multiple circuits if they have different characteristics. Obviously, if you have differing voltage or phase needs such as 208/120V and 480/277V, that is allowed. But the example specifically cites "different uses, such as control of outside lighting from multiple locations".
 

renosteinke

Senior Member
Location
NE Arkansas
Very good catch! I would say that (D) does cover this use- though you'd never know it without that example being given.

I had reviewed 225.30 before I started this thread, and I even recall looking at (D). I got far enough in to see 'different characteristics' before I moved on - after all, how can the end of a branch circuit be characteristically different from the beginning?

Maybe that's what I needed to ask: Does a switch on a circuit make it have 'different characteristics?" Or, more specifically, does using a 3-way switch alter the characteristics? What are 'characteristics' anyway?

IMO, this is one part of the code that needs some serious editing.

Good to see we can still control lights the 'old fashioned way,' even if the homeowner later adds a panel to the garage.
 

david luchini

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Staff member
Location
Connecticut
Occupation
Engineer
I don't see that there is any 225.30 violation if a structure (garage) that is served with a single branch circuit from another structure subsequently is supplied with its own Service and the original branch circuit is left in place.

225.30 prohibits supplying a structure supplied by a branch circuit or feeder on the load side of a service disconnecting means from being supplied by an additional feeder or branch circuit...It says nothing about being supplied by a Service.

Both sections 225.37 and 230.2(E) address Identification requirements for when a structure is supplies by a combination of services, branch-circuits and feeders.
 

mgookin

Senior Member
Location
Fort Myers, FL
...
Both sections 225.37 and 230.2(E) address Identification requirements for when a structure is supplies by a combination of services, branch-circuits and feeders.

I had the same thought reading through the thread. If I were AHJ on that job I'd at the most ask that you install another disconnect on the lighting circuit where it gets to the subject building (a garage) and identify both locations as disco 1 of 2... 2 of 2. That way anyone working on that building is not going to get fried. That's what it's all about.
 
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