How to properly disconnect detached structure?

[ritelec]

No detached building wiring coming up, but wondering.

It never made sense to me how if a panel is installed, that an exterior disconnect is needed, or the panel would need to be located right as you enter.

What about a house where that panel is fed from? Around here most main panels (and disconnect) are located behind locked doors usually down in the corner of a basement.

Doesn't make sense.

If there's an exterior disconnect, does the driven rod (or two) go to the disconnect ground, or the panel ground.


From what I understand, one circuit does not need a disconnect at the detached structure, But two or more circuits would.
How do you do it? 2 pole and 3 pole switches in exterior boxes? Or ganged up single poles?
Could what ever disconnect that is used also be right inside the entrance?

Where does this leave a light that you want. A light on the detached structure and the house which come on together. And the 3-way switch at the detached structure that controls those two lights?

Thank you

 

[GoldDigger]

How about the end with the circuit that feeds the light can have the switch either inside or outside but at the other end the light and switch are both outside the building so that the circuit never enters that building?

Tapatalk!

 

[kwired]

No detached building wiring coming up, but wondering.

It never made sense to me how if a panel is installed, that an exterior disconnect is needed, or the panel would need to be located right as you enter.

What about a house where that panel is fed from? Around here most main panels (and disconnect) are located behind locked doors usually down in the corner of a basement.

Doesn't make sense.

If there's an exterior disconnect, does the driven rod (or two) go to the disconnect ground, or the panel ground.


From what I understand, one circuit does not need a disconnect at the detached structure, But two or more circuits would.
How do you do it? 2 pole and 3 pole switches in exterior boxes? Or ganged up single poles?
Could what ever disconnect that is used also be right inside the entrance?

Where does this leave a light that you want. A light on the detached structure and the house which come on together. And the 3-way switch at the detached structure that controls those two lights?

Thank you

Which code year applies, there were some changes in 2014, mostly in 225.36.

The disconnecting means only need to be suitable for use as service equipment if in a situation (where permitted) to use the grounded conductor (neutral) for equipment grounding purposes - basically an old feeder that was once permitted without a separate EGC. Also the exception allowing you to use a three way or four way switch as the disconnecting means has been deleted in the 2014.

For the light on the house and detached structure that you want to come on together - read the last sentence in 225.30

"Where a branch circuit or feeder originates in these additional buildings or other structures, only one feeder or branch circuit shall be permitted to supply power back to the original building or structure, unless permitted in 225.30(A) through (E)"

this would allow you to start the circuit from the detached structure and feed back to the main structure. (I think that part was new in 2011).

Read through art 225 part II carefully and you may find answers to some of your questions.

 

[ritelec]

Sorry for the bump.

Just wanted to thank you for the response.

I will read into it.

 

[Strathead]

No detached building wiring coming up, but wondering.

It never made sense to me how if a panel is installed, that an exterior disconnect is needed, or the panel would need to be located right as you enter.

What about a house where that panel is fed from? Around here most main panels (and disconnect) are located behind locked doors usually down in the corner of a basement.

Doesn't make sense.

If there's an exterior disconnect, does the driven rod (or two) go to the disconnect ground, or the panel ground.


From what I understand, one circuit does not need a disconnect at the detached structure, But two or more circuits would.
How do you do it? 2 pole and 3 pole switches in exterior boxes? Or ganged up single poles?
Could what ever disconnect that is used also be right inside the entrance?

Where does this leave a light that you want. A light on the detached structure and the house which come on together. And the 3-way switch at the detached structure that controls those two lights?

Thank you

If I misunderstand your writing I apologize up front, but the location of the disconnect does not need to be "located right as you enter" it needs to be located right where the service or feeder conductors enter. There is a little wiggle room for AHJ interpretation, but when feeders are run underground they are not considered entering the structure until the come up out of the ground. That goes for services and separate structures. Now that is not to say that many older buildings in your area are compliant, I know that in the county I live in almost any house built in the 70's violates this requirement with a meter on the outside and 2 hots and a neutral run in to the panel inside. Any time you upgrade a service, you have to fix this though.

 

[kwired]

...almost any house built in the 70's violates this requirement with a meter on the outside and 2 hots and a neutral run in to the panel inside. Any time you upgrade a service, you have to fix this though.

What you describe there is not a violation... at least without more details. The meter is not the service disconnect the panel inside is, unless you have a "meter/main" which you did not make all that clear. Where ever the service disconnecting means is the point where you need to start running equipment grounding conductors separate from grounded conductors. The distance that service cable enters the structure is also another possible violation, and NEC has never been definite on any length for this but many local jurisdictions have been with amendments.

 

[Strathead]

What you describe there is not a violation... at least without more details. The meter is not the service disconnect the panel inside is, unless you have a "meter/main" which you did not make all that clear. Where ever the service disconnecting means is the point where you need to start running equipment grounding conductors separate from grounded conductors. The distance that service cable enters the structure is also another possible violation, and NEC has never been definite on any length for this but many local jurisdictions have been with amendments.

Yeah I got lazy. Actual situation is Meter outside. Conductors run through the attic, to a location far inside, often 30 feet across the house to an interior location. Last sentence was the AHJ interpretation I was referring to. For some I have seen as much as ten feet. Too much for me if I was the AHJ. 3-4 feet is ok for me. Out of the ground, one local doesn't allow a fill 90 or anything like an LB. Up from the ground ring in to the bottom of the disconnecting means for example

 

[ritelec]

If I misunderstand your writing I apologize up front, but the location of the disconnect does not need to be "located right as you enter" it needs to be located right where the service or feeder conductors enter. There is a little wiggle room for AHJ interpretation, but when feeders are run underground they are not considered entering the structure until the come up out of the ground. That goes for services and separate structures. Now that is not to say that many older buildings in your area are compliant, I know that in the county I live in almost any house built in the 70's violates this requirement with a meter on the outside and 2 hots and a neutral run in to the panel inside. Any time you upgrade a service, you have to fix this though.

OK, like I said, I will have to read more into it.
I thought either external or right at the entry.

And around here, meters on the outside, hot wires from utility a few feet into building (usually basement) to main disconnect.

"located right as you enter" as opposed to "located right where the service or feeder conductors enter"., doesn't make sense.

If entry location was in the back of the structure 10' or 110' away, you wouldn't be able to disconnected it without entering and walking in.


(as I write this I think the lightbulb just went off. They aren't necessarily saying "we want to be able to turn power off before or as we enter" but rather " we want to be able to turn power off before or where power enters the building so NO live wires are running through the building", "even if I have to walk 400' to get to that disconnect or panel"," once I get to that panel 400' away in the structure and turn it off, I know there are no live circuits or feeders in the building".)


I might ad that I can see this, in my shed install 25 yrs ago, the feed comes in (no disconnect) then goes across the inside (30') to where I install a main lug 12c panel, no ground rod(s)

I did have it inspected ! Grandfather?

I shall read on.

Thank you.

 

[kwired]

(as I write this I think the lightbulb just went off. They aren't necessarily saying "we want to be able to turn power off before or as we enter" but rather " we want to be able to turn power off before or where power enters the building so NO live wires are running through the building", "even if I have to walk 400' to get to that disconnect or panel"," once I get to that panel 400' away in the structure and turn it off, I know there are no live circuits or feeders in the building".)

I think that is the main intent.

I might ad that I can see this, in my shed install 25 yrs ago, the feed comes in (no disconnect) then goes across the inside (30') to where I install a main lug 12c panel, no ground rod(s)

Though buildings supplied by a feeder have similar requirements as services, I personally have less issue with entering the building for such a distance with a feeder that has overcurrent protection ahead of it then I do with having a service conductor with no protection besides the transformer primary protection ahead of it installed in a similar manner.

 

[GoldDigger]

The other factor, at least important as disconnecting, is that there is no suitable overcurrent protection on the service wires. The OCPD is at the service disconnect. So service wires inside the building are a greater fire hazard than non service wires carrying the same current under normal conditions. The length they are inside the building needs to be minimized.


Tapatalk!

 

[mwm1752]

Seems the readily accessible location would determine the distance in which the unfused conductors can enter a building. Protection can be per 230.43 while inside or use 230.6 to keep it considered outside the structure.

230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.
(A) Location. The service disconnecting means shall be installed in accordance with 230.70(A)(1), (A)(2), and (A)(3).
(1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.
230.32 Protection Against Damage.
Underground service-lateral conductors shall be protected against damage in accordance with 300.5. Service-lateral conductors entering a building shall be installed in accordance with 230.6 or protected by a raceway wiring method identified in 230.43.

 

[Strathead]

Seems the readily accessible location would determine the distance in which the unfused conductors can enter a building. Protection can be per 230.43 while inside or use 230.6 to keep it considered outside the structure.

230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.
(A) Location. The service disconnecting means shall be installed in accordance with 230.70(A)(1), (A)(2), and (A)(3).
(1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.
230.32 Protection Against Damage.
Underground service-lateral conductors shall be protected against damage in accordance with 300.5. Service-lateral conductors entering a building shall be installed in accordance with 230.6 or protected by a raceway wiring method identified in 230.43.

Not at all. Article 100 definitions: Accessible Readily, Capable of being reached quickly for operation, renewal or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders so forth.

Has nothing to do with how far.