Jump to content

How far?


Chad Fabry
 Share

Recommended Posts

Hi Chad,

I guess that will depend on what it's delivering at the other end. It has to deliver between 108 and 132 volts. If it's too long, I suppose it could drop below that minimum, although I think a house would have to be gargantuan to cause that much drop from the meter to the panel.

ONE TEAM - ONE FIGHT!!!

Mike

Link to comment
Share on other sites

Hi Again,

Here's Hansen on the subject:

From Electrical Inspection of Existing Dwellings - 2001 Edition by Douglas Harden, Redwood Kardon & Michael Casey.

Some jurisdictions set a maximum length of service conductor between the point of entry to the building and the service equipment. The longer the distance of unprotected service conductor, the greater the chances for damage. Service conductors sometimes travel through an attic before reaching service equipment, though most often the cable runs a short distance through the basement wall.

ONE TEAM - ONE FIGHT!!!

Mike

Link to comment
Share on other sites

NEC 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.

I've always read that as meaning the service panel should basically be on the other side of the wall from where the SECs enter and I really can't remember a home where that wasn't the case. Looking at my Illustrated Guide the notes say the length is unspecified but should be kept to a minimum. It also says that some AHJ's define the maximum length (?).

So...dunno, but Brandon's 25' seems quite excessive!

Link to comment
Share on other sites

Chad I think Richard is dead on the code quote.

I think the service equipment means the meter base and, if the distribution panel is remote, an outside disconnect means right with the meter base.

From there on inside is called a feeder, and the panel is a sub-one.

As long as the feeder is covered by overcurrent protection, I don't think code cares how far, until you start hitting voltage-drop lengths.

Link to comment
Share on other sites

Hi,

You're forgetting regional differences, Jim. It's true that the service entrance conductors begin at the weatherhead and go to the meter, but the service disconnect isn't always at the meter. It's not uncommon, around here anyway, to find a meter on one side of a building and the panel and main disconnect inside the building on another side. In those case, since the panelboard contains the service disconnect it is not a sub-panel and is configured as a main panel. The service grounding electrode connects in those panels and the EGC's and grounded conductors share the same bar and bonding is present. From that point onward, other panels are sub-panels.

Sometimes those panelboards will be fed with a conduit that passes through the wall, goes through the attic and then drops down into the house; sometimes they pass around the outside of the house under the eaves - either in a conduit or outside of conduit and attached at proper (or not) intervals to the house.

Not too long ago, a fellow posted a query here wherein he had found this strange panel configuration with the main disconnect inside the panel and the panel inside the home instead of on the outside of the home. I had to chuckle 'cuz I think I've seen about half a dozen exterior service entrance setups here in the 12 years I've been doing this and only about the same number where the main disconnect was a throw separate from the main service panel.

ONE TEAM - ONE FIGHT!!!

Mike

Link to comment
Share on other sites

"Sometimes those panelboards will be fed with a conduit that passes through the wall, goes through the attic and then drops down into the house..."

Can't say I've ever seen that Mike. Based on my understanding of "the point of entrance" I think I would have to call it as wrong if I did. Isn't the intent to minimize any wiring without OCPDs within the home? I don't see that it matters if it is in conduit or if it's an attic or basement. Inside is inside.

Link to comment
Share on other sites

Originally posted by Richard Moore

"Sometimes those panelboards will be fed with a conduit that passes through the wall, goes through the attic and then drops down into the house..."

Can't say I've ever seen that Mike. Based on my understanding of "the point of entrance" I think I would have to call it as wrong if I did. Isn't the intent to minimize any wiring without OCPDs within the home? I don't see that it matters if it is in conduit or if it's an attic or basement. Inside is inside.

Hi,

Well, I've seen quite a few. They're never pretty, but I don't think there's anything "wrong" with those installations as long as the cable is protected from damage. That means either in an approved conduit or secured to the building in such a way and at such a location that it isn't likely to be damaged.

Here's Hansen

The NEC defines the service equipment as the breakers/switches/fuses and related quipment that are on the load end of the service and provide the means of disconnecting the power. Once the electrical service has passed though the service equipmen, it has protection so that a short circuit, ground faulkt, or overload would not simply cause the conductors to burn..
He doesn't say anything anywhere about the panel being required to be close to the meter can (see my previous quote above) - only that one must be careful to protect those cables because they don't have OCPD protection on them until after the panel. Like you, I think it's dumb, and I wouldn't necessarily like to see it in my own home, but I don't think it's a hill to die on 'cuz I think it's allowed.

Try narrowing the focus of your thinking; instead of a single-family residence, think of a condo building where the service entrance panels are all grouped in one room deep inside the structure. In those cases, you have heavy conduit passing completely through the building to that utility room. It's the same thing with a single-family home, except that the meter can is on the outside of the building, and the panel, instead of being directly on the other side of the wall from the meter, or ten or twelve feet below it in the basement, is deeper in the structure.

ONE TEAM - ONE FIGHT!!!

Mike

Link to comment
Share on other sites

"He doesn't say anything anywhere about the panel being required to be close to the meter can..."

No, I don't care about the meter being close to the panel. My own runs from the meter at the front of the house to close to the rear, but it's in conduit along the outside. Very typical. My concern is strictly the distance once the "penetration" has been made.

Condos??? Well, I'm not sure that is narrowing my focus, but I assume we're talking about high-rises, as opposed to smaller condos. True, the service sometimes enters those along conduit to the electrical room, but that's typically in the common garage, which has it's own fire protection from the living quarters. My problem with the attic or basement in an SFR is the lack of "fire-wall" separation.

"...but I don't think it's a hill to die on..."

Agreed, and probably not a huge issue if protected in conduit...just trying to understand if it's actually is allowed, 'cos I'm still not sure.

Link to comment
Share on other sites

As Richard pointed out, the NEC does not specify a measurement for the distance the service conductors can pass through a building before they terminate in the service equipment. It is up to the AHJ to determine that the intent of "as close as possible to the point of entrance of the service conductors" has been met. I know of one municipal inspector that has set the maximum distance at 6'.

Link to comment
Share on other sites

A travelling panel of electric engineers, putting on a code review for local electric license holders, was asked directly how far, and they squirmed and fidgeted, but would not name a number.

The idea is that if the distribution panel is not "back to back", then it needs the outside disconnect and the four wire feeder to the "subfed" dist panel.

That's how it is down here in the Ga pines, anyway.

Link to comment
Share on other sites

Originally posted by Chad Fabry

Is there a maximum distance that the SEcable can be run after it enters the structure before it is connected to the service equipment?

Here is the relevent section from the NEC:

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 no maximum distance, just "nearest the point of entrance of the service conductors." This restriction first appeared in the 1984 NEC.

Some states and some AHJs might have specific distances but the NEC doesn't.

- Jim Katen, Oregon

Link to comment
Share on other sites

  • 4 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...