Service Rigid Pipe

[bennie]

Re: Service Rigid Pipe

A switch at 6'7" will be the closest point of intercepting the service entrance, regardless of where the conductors arrive at the structure.

There are many underground services imbedded in the exterior walls of houses, around this area.

This points out the non-uniformity of applying the code. There is technically nothing wrong with either procedure.

 

[hurk27]

Re: Service Rigid Pipe

What happen to that thread about what would happen if the service entrance conductors would short out. we all know that the fuses on the primary side of the transformer only protect the line feeding the transformer not the secondary wires. and in most cases the wires would burn clear but if there inside of RMC they will most likely keep burning untill the service drop drops. and I would guess that the structure would be on fire by then.

 

[iwire]

Re: Service Rigid Pipe

Originally posted by bennie:
This points out the non-uniformity of applying the code.

Yes that is for sure.

I have never seen a meter socket made for flush mounting, they are just not used in this area.

Overhead or underground gets a surface meter socket.

 

[ccf]

Re: Service Rigid Pipe

Gentlemen - thank you very much for all your responses, this is really a great forum because we all learn something new everyday.

Can we go back to my main question?

Is there anything in the NEC that says you cannot go horizontal, even for just 6" - knowing already that in Los Angeles, in-wall service is preferred in new construction?

Again, my illustration is what we have now...
http://www.ccforteza.com/rigid.pdf

 

[bennie]

Re: Service Rigid Pipe

230.53 Raceways To Drain. This section appears to be the only reference that may indicate a problem with horizontal conduit.

 

[bill addiss]

Re: Service Rigid Pipe

Bob,

I had questions similar to yours about the riser in the wall here's a picture sent to me of an all-in-one that I was told was typical of installations in Ca:

Here's another:

In the picture below the original service riser was in the wall, (right side) but on an upgrade the new Equipment was surface mounted.

Bill

 

[al hildenbrand]

Re: Service Rigid Pipe

CCF,

The question you are asking was, in my opinion, solidly covered by Charlie's response (third after your question). The NEC won't answer your question, the Authority Having Jurisdiction (over your building's electrical wiring) will have the answer.

NFPA 2002 NEC Handbook commentary following 230.70(A)(1)

No maximum distance is specified from the point of entrance of service conductors to a readily accessible location for the installation of a service disconnecting means. The authority enforcing this Code has the responsibility for, and is charged with, making the decision as to how far inside the building the service-entrance conductors are allowed to travel to the main disconnecting means. The length of service-entrance conductors should be kept to a minimum inside buildings, because power utilities provide limited overcurrent protection and, in the event of a fault, the service conductors could ignite nearby combustible materials.

Some local jurisdictions have ordinances that allow service-entrance conductors to run within the building up to a specified length to terminate at the disconnecting means. The authority having jurisdiction may permit service conductors to bypass fuel storage tanks or gas meters and the like, permitting the service disconnecting means to be located in a readily accessible location. However, if the authority judges the distance as being excessive, the disconnecting means may be required to be located on the outside of the building or near the building at a readily accessible location that is not necessarily nearest the point of entrance of the conductors.

The Handbook commentary is not regulatory language.

 

[bennie]

Re: Service Rigid Pipe

The main panel and riser will dissipate heat much better when placed in the wall. The solar heat, in parts of California, will cook the surface mounted panel.

 

[noxx]

Re: Service Rigid Pipe

well it just goes to show ya...

Personally, I am another california electrician, and yes it's the standard, preferred procedure to run a 1.5 or 2" rigid riser concealed in the wall to a flush mount panel for overhead services.

The rigid penetrates two points, the roof, and the top plate, and provides a very solid point of attachment for the service conductors. Like Bennie, I was unaware of any code issues regarding this type of standard installation (not the one pictured in the original question) because that's simply how it's done here, never occurred to me to do it otherwise.

When permitting a service change in any city in southern cal, you are usually handed a standard diagram of an "acceptable" installation, which includes the in-wall conduit.

I'm baffled, that you're baffled, lol. I guess now I have some idea how you folks felt when I was so taken aback by the use of surface mounted SEC (which I still maintain is nothing more than a giant, glorified, Romex tacked to the wall of a home and about as attractive.).

The code may be "national" but you're right, it's certainly not "uniform".

 

[iwire]

Re: Service Rigid Pipe

Originally posted by noxx:
I'm baffled, that you're baffled, lol.

Well said

I would love to see the look on an inspectors face if he came out to a job I did that way.

I am not saying it is a bad way, just a way not allowed here.

I really can not imagine a fault happing inside a RMC inside a wall.

 

[rickg]

Re: Service Rigid Pipe

In Bill's third picture of the 5 meter upgrade, is that a piece of cardboard covering the live meter jaws???I would be on the phone to that electrician to immediately get a listed blank up on that socket or power will be terminated.
I know that Bill did NOT do this installation.
Rick

 

[bennie]

Re: Service Rigid Pipe

In California, the utility company established the standard method for installing a service.

It is the only State I have seen that has a uniform procedure. The weather differences created a need for positive securing of the service drop. The riser mast was the critical part. The structure is used for insuring the strength of the mast.

The riser, shown in the photo, would not last through one good wind storm.

Wind, causing a drop to swing and vibrate, will cause any wood secured dead eye to pull out of the framing.

The rate of incidence of a short inside the riser is a non-issue. NFPA and California Electrical Safety records can be checked for verification.

A case can be made by examining the amount of exposure, of a conduit inside the wall versus one mounted on the exterior surface. A house, with wood siding, would be exposed to ignitable material the same in both locations. The sheetrock is the only fire barrier, and it is present in both scenarios.

 

[bennie]

Re: Service Rigid Pipe

Furthermore: The recessed panels and meter bases are UL listed only for "in the wall" installation. The enclosure is not raintight, only the front covers.

California required a main breaker, on all residential services, 50 years ago. Many States still allow 6 switches in the main.

I recently sold a family owned property in California. I installed the service 40 years ago. I removed most of the covers and dead fronts to see how the material was retaining insulation integrity. The insulation was TW, but appeared to be in good shape.

 

[iwire]

Re: Service Rigid Pipe

Bennie I am not saying it is a bad method.

I do not agree it is necessarily a better way, what ever works for a particular region is the way to go.

If it works good for CA great, around here it would be a tough sell.

I am glad that around here almost all main panels are in the basement or garage, standing in snow to work on a panel never makes me happy.

 

[iwire]

Re: Service Rigid Pipe

Originally posted by bennie:
Furthermore:

 

[bennie]

Re: Service Rigid Pipe

Bob: I agree, this points out that one method is not always the best for all locations.

California is famous for the panels opening to the outdoors. This is a calculated design for the yearly weather changes.

In the summer the back of the panel uses the sheetrock as a heat sink.

In the winter, the panel is cooled by the ambient outdoor temperature.

 

[iwire]

Re: Service Rigid Pipe

Well I can certainly see how a mast supported in this way would be strong.

Is it a problem making a permanent weather proof seal between the roof and the RMC?

I have never had to do a mast the passed through the roof, the only masts I have done ran outside of the roof.

The last one I did was 4" RMC for a 400 amp service, the upper supports where uinstrut with threaded rod passing through the wall into the attic with 3" deep unistrut inside spreading the force out over 3 studs, the wall will be pulled off before the hardware lets go.

 

[russellroberts]

Re: Service Rigid Pipe

Bob,we always use a roof jack or boot when going through the roof. It's the same thing a plumber uses on vent pipes. Take a shingle or two loose and slide it under them,then the boot,replace the shingles and you get a good weatherproof seal.

Russell

 

[iwire]

Re: Service Rigid Pipe

That makes sense I penetrate a lot of flat roofs for roof top units and around here we use a thing called a witches hat for that. It uses a spiral clamp to seal to the pipe and the roofers glue it to the rubber membrane.

I was wondering if the seal for a mast breaks down from movement of the mast.

 

[russellroberts]

Re: Service Rigid Pipe

The ones we use have a rubber center where the hole is while the rest of it is hard plastic.

The rubber allows for some movement. The older ones were metal with a rubber center. I think you can still get these.

I've never seen on go bad,but I'm sure it could happen,probably more from the sun than movement.

We don't build many oh services here,but when we do,I always put in some blocking in the soffit so it can't move much.


Russell

[ November 16, 2003, 10:26 AM: Message edited by: russellroberts ]