Residential Service Meter Question

In the UK, the "company" fuses (belonging to the supply company) are before the meter. After the meter is the customers consumer unit (formerly fuseboard).

Not in the US. Service conductors are basically unfused all the way from the service disconnect in the main panel to the pole transformer where the primary side is fused (virtually zero protection on the

120/240 secondary side).

That's right.

And that's why the service panel has to be quite close to the service entrance.

** Posted from **

It can be remote, but you have to have a fused disconnect at the meter base. I've never personally seen it done this way, but I've seen pictures. Generally it's when the panel is down in a basement.

If it has a fused disconnect at another place it is a feeder supplied panel. By definition a service panel; or more properly a panel used as service equipment contains the Service Disconnecting Means. If the Service Disconnecting Means is located any were else it is not a service panel.

On Mon, 26 May 2008 04:02:23 GMT James Sweet wrote: | | John Gilmer wrote: |>> Not in the US. Service conductors are basically unfused all the way |>> from the service disconnect in the main panel to the pole transformer |>> where the primary side is fused (virtually zero protection on the |>> 120/240 secondary side). |> |> That's right. |> |> And that's why the service panel has to be quite close to the service |> entrance. |> | | | It can be remote, but you have to have a fused disconnect at the meter | base. I've never personally seen it done this way, but I've seen | pictures. Generally it's when the panel is down in a basement.

A previous house I lived in, built in the late 1960's, had a triplex drop to the side of the house at the apex of the roof. From there a USE style cable ran down along the side of the roof to the corner, then along under the roof eave in the back to about the middle. There it hit the meter. Below the meter the cable run about 2 more feet and entered the wall where it came out inside the basement. Only part of the house had a basement. That cable ran another 1.5 feet before it reached the panel mounted on a wall at a 90 degree angle against the outside wall. It was a 200 amp QO panel with a larger vertical main rated 200 amps, possibly a QBL22200. Anyway, there was a lot of unprotected outside cable run, at least 40 feet of it. I don't know how they might have to do it today.

There is really no limit to the length of SE cable "outside" the building. The limit "inside" is somewhat ambiguous in 230.70(A)(1) but should be as short as possible.

230.70(A)(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.

| There is really no limit to the length of SE cable "outside" the | building. The limit "inside" is somewhat ambiguous in 230.70(A)(1) but | should be as short as possible.

I knew there was no limit outside back then. So still not.

| 230.70(A)(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.

The inside panel could not have been in any different location. Had it been on the outside wall nearest the hole bringing the power in, it would have actually been a longer run of unprotected cable, having to skip over a window which could not be moved due to the exterior rear porch.

One of the problems with doing a service disconnect outside right at the meter is that the ground bond has to be done there, and surge protection needs to be done at the ground bond, but surge protection equipment often cannot be put outside, or needs larger equipment. What one has to do is design the house floor plan around things like electrical service entrance. That house was designed by my mother, and she let the electrician figure out where to put most of the electricals (she simply specified where major appliances would be, and I specified locations in my own bedroom to ensure they didn't get blocked by furniture).

It is acceptable to run the service entrance cable outside of the structure. If you bury it in 2" minimum concrete it is generally considered equivalent of outside. The concern is when it runs inside, where it could cause a fire if it burns up. The Code is not specific about a maximum length. The AHJ has the final say as to what is acceptable.