Suggestions for fixing an underground fed meter base falling off house

Status
Not open for further replies.
peter d said:
It is a POCO spec in my area, as well as being NEC required.
Click to expand...
I accept the fact that POCO's in your area call for the expansion fittings on UG services. I can't find anything in the 2014 NEC that is specific to a UG service requirement for an expansion fitting. I've looked through the installation manuals for the (3) POCO's in my area and none of them call for an expansion fitting on a UG service.

I don't want to pirate this thread away from the OP but frankly I can't understand the use of an expansion fitting on a UG service. If the ground settles and pulls the PVC and meter pan down doesn't the wire pull down as well (as shown in the OP)?
 
goldstar said:
I can't find anything in the 2014 NEC that is specific to a UG service requirement for an expansion fitting.
Click to expand...

My oldest NEC on my computer is 2002 and here it is

300.5(J) Ground Movement. Where direct-buried conductors,
raceways, or cables are subject to movement by settlement
or frost, direct-buried conductors, raceways, or cables shall
be arranged to prevent damage to the enclosed conductors
or to equipment connected to the raceways.


FPN: This section recognizes “S” loops in underground
direct burial to raceway transitions, expansion fittings in
raceway risers to fixed equipment, and, generally, the provision
of flexible connections to equipment subject to
settlement or frost heaves.
Click to expand...

Now does that section specifically require an expansion joint?

No, not in my opinion.

However it does require something be done about frost movement in colder climates. So what are you doing to comply with this section if you are not using an expansion fitting?
 
goldstar said:
I accept the fact that POCO's in your area call for the expansion fittings on UG services. I can't find anything in the 2014 NEC that is specific to a UG service requirement for an expansion fitting. I've looked through the installation manuals for the (3) POCO's in my area and none of them call for an expansion fitting on a UG service.

I don't want to pirate this thread away from the OP but frankly I can't understand the use of an expansion fitting on a UG service. If the ground settles and pulls the PVC and meter pan down doesn't the wire pull down as well (as shown in the OP)?
Click to expand...

We don't use expansion fittings for UG here, either. I don't think such a fitting would have helped the OP at all, as it does look like the conductors are bow string tight and pulled the box down.
 
iwire said:
My oldest NEC on my computer is 2002 and here it is



Now does that section specifically require an expansion joint?

No, not in my opinion.

However it does require something be done about frost movement in colder climates. So what are you doing to comply with this section if you are not using an expansion fitting?
Click to expand...
OK thanks. That code section didn't show up in the index under expansion fittings. Do POCO's really leave slack on UG services? Haven't seen that done in my area yet.
 
K8MHZ said:
We don't use expansion fittings for UG here, either. I don't think such a fitting would have helped the OP at all, as it does look like the conductors are bow string tight and pulled the box down.
Click to expand...

So I ask you, how is your area complying with the requirements for ground movement?
 
goldstar said:
Do POCO's really leave slack on UG services? Haven't seen that done in my area yet.
Click to expand...

I really do not know but we as ECs can leave slack in the meter socket.

If the power company handles installing those conductors in your area I would say the NEC section I posted does not apply. :)
 
K8MHZ said:
I guess they don't. See page 34 of this pdf:
Click to expand...

So you are saying in your area these conductors and raceways are under utility control? If that is the case of course the NEC does not apply.

In many areas the EC installs these conduits and they are under NEC rules.

Now if you ran an underground feeder or branch circuit in to a remote building and entered it above grade how would you comply with the NEC?
 
goldstar said:
I don't want to pirate this thread away from the OP but frankly I can't understand the use of an expansion fitting on a UG service. If the ground settles and pulls the PVC and meter pan down doesn't the wire pull down as well (as shown in the OP)?
Click to expand...

I am also a huge fan of expansion couplings or slip risers after seeing a zillion failures. Just two weeks ago fixed one very similar to th OP picture. Yes, a loop or s curve in the conductors is required or the expansion coupling may do no good.
 
iwire said:
So you are saying in your area these conductors and raceways are under utility control? If that is the case of course the NEC does not apply.

In many areas the EC installs these conduits and they are under NEC rules.

Now if you ran an underground feeder or branch circuit in to a remote building and entered it above grade how would you comply with the NEC?
Click to expand...

I am not 'saying' anything. That pdf. was from the POCO and those drawings are what we must go by if we want to be connected.

It's a weird deal here. See note 1 on page 32. For underground, POCO owns meter socket, but customer must install meter socket (we pick them up at the service center, no charge, no paperwork) POCO owns and installs service riser conduit and service conductors.

For underground branch circuits, if the area is not zoned agricultural, for residential we follow the Michigan Residential Code, for the rest we follow the NEC. There is no inspection or permits required for agricultural.

Neither the NEC nor the MRC requires expansion fittings for stubs coming from the ground to an enclosure. Expansion fittings are only required for conduit secured box to box or fitting.

If the entire run is underground, the temp change will be minimal, so no expansion needed there. from the ground up, the run will be so short that none will be needed there.
 
Frost heave - put the buried raceway/cable below the maximum frost dept for your area. There may still be some strain on the vertical rise but there probably is some slip to it as well.

Settling - make sure to dig down to undisturbed soil and either make your underground run just as deep or compact the soil below your underground run. OP's situation is very common on newer construction where the soil next to the basement wall had been excavated to construct the basement wall. Sometimes it can take a few years before a significant rain event comes along and it suddenly settles if no compaction during backfill was performed. This also causes failures of decks, steps patios, and sidewalks sometimes.

Expansion fittings are for protecting the raceway from movement, not the conductors within. You can put some slack on those conductors if you think it will help, but start getting over about 1/0 AWG and they don't bend as easily, then put them in a cold ambient and they get even harder to bend.

A expansion joint in the OP may have saved from having the raceway pull the box loose, but if the conductors within are still being pulled it would have strained the terminations, and in that particular style of meter cabinet where conductors go straight down, probably would have pulled the box from the wall anyway, or if box were secured solid enough would have broken a lug or other components.
 
K8MHZ said:
I am not 'saying' anything. That pdf. was from the POCO and those drawings are what we must go by if we want to be connected.
Click to expand...

You are 'telling me' that these conductors are utility controlled so the NEC does not apply.


Neither the NEC nor the MRC requires expansion fittings for stubs coming from the ground to an enclosure. Expansion fittings are only required for conduit secured box to box or fitting.
Click to expand...

Have you read the thread?:roll:

I stated very clearly that the NEC does not directly require an expansion fitting for ground movement. So I ask you again, if you choose not to use an expansion fitting what are you doing to comply with what the NEC does require in the ground movement section?


If the entire run is underground, the temp change will be minimal, so no expansion needed there. from the ground up, the run will be so short that none will be needed there.
Click to expand...

This has nothing to do with the discussion.
 
kwired said:
Frost heave - put the buried raceway/cable below the maximum frost dept for your area. There may still be some strain on the vertical rise but there probably is some slip to it as well.

Settling - make sure to dig down to undisturbed soil and either make your underground run just as deep or compact the soil below your underground run. OP's situation is very common on newer construction where the soil next to the basement wall had been excavated to construct the basement wall. Sometimes it can take a few years before a significant rain event comes along and it suddenly settles if no compaction during backfill was performed. This also causes failures of decks, steps patios, and sidewalks sometimes.

Expansion fittings are for protecting the raceway from movement, not the conductors within. You can put some slack on those conductors if you think it will help, but start getting over about 1/0 AWG and they don't bend as easily, then put them in a cold ambient and they get even harder to bend.

A expansion joint in the OP may have saved from having the raceway pull the box loose, but if the conductors within are still being pulled it would have strained the terminations, and in that particular style of meter cabinet where conductors go straight down, probably would have pulled the box from the wall anyway, or if box were secured solid enough would have broken a lug or other components.
Click to expand...

You will fail inspection here and all the other contractors will laugh at you. :p
 
iwire said:
You will fail inspection here and all the other contractors will laugh at you. :p
Click to expand...
Many do here as well, but I still find expansion fittings somewhat useless in many risers from underground regardless of what codes or others have to say.

I have seen 3 and 4 inch expansion fittings into CT cans that are close to the ground and the concrete is poured around the expansion fitting - making it just as effective as no expansion at all. But POCO was happy because they require an expansion fitting there:roll:
 
Status
Not open for further replies.
Top