In our area most underground services were once installed using EMT. The conduits are all in need of replacement now. Is this the same situation everywhere? Just Curious.




Bill

Bill,
The UL white book says: "In general, galvanized steel EMT in contact with soil requires supplementary corrosion protection."
The utility in this area does not permit EMT for services. Most are PVC with some rigid and a very few IMC.
Don(resqcapt19)

Here in miami, when its underground, we use (for most residential services)a 2" Rigid down pipe (it has to go down 2 feet) the cable in the down pipe is either direct burial triplex, or its sheathed in 2" sch. 40 PVC back to the pole. in some places i have seen that 2" rigid pipe rust pretty badly.. thats what you get for having a water table 6-8 feel below the ground

-m

Bill,

Here in NC I have seen that a time or too. In this field there is never a dull moment,and just when you think you have seen it all bam here we go again.
Even though we try to do our best at the time of installation. There are always beter materials and methodology being developed all the time.
It's always interesting to see these types of situlation. It gives us a better insight of what we all can or may encounter in our field.

Wayne

Up here in the green mountains the earth is all bones, remnants of some ancient meteor no doubt.
So direct burial is usually frowned on, most of what i see is in pvc , once in a while rigid

Here in the evergreen state, EMT is not used if it will be in direct contact with the earth. Also can't use it for an aboveground service raceway.

Was EMT ever approved for this use?
Every underground residential service I've seen from, say 30 years ago was done in this way (and looks like this). We've got a whole lot of pipes to replace here.

Bill

I hate to say it, but here in the Mountain State, if it had a circular cross section, it was used as a raceway. I've had to turn down a few re-connects because of EMT being used. EMT was never approved here in WV for contact with the earth, but, since no one ever said "nope" for a long time, it was used.

I'm guessing, but I think it was the early eighties when it was banned. The reason they banned it for service raceway was because people were only hand-tightening the EMT compression couplings and connectors. Guess they were too lazy to reach for their channel locks!

Very common on old work around here. I have replaced lots of these with PVC....usually after repairing the UG that was damaged by the collapsing, rusted emt.

GJ

If EMT was ever legal to use for underground of any kind, it shouldn't have been. I used to have a 1975 NEC. I think I'll try to find that old code book, and look it up.

Here in Houston you will see PVC, and RMC if Houston Lighting & Power standards are to be met. We've done jobs where the engineer required PVC coated RMC (Plastabond), concrete encased PVC, or coated RMC. I've been on jobs where stainless was required for all exposed conduit runs.

IMHO PVC is the best for underground, then convert to RMC where subject ot damage. If you see coated RMC in the spec's for a job, it is usually an older engineer who won't give up the "old methods". Heck, the NEC even allows PVC for undergroung in gas stations. Have a nice day......

HMEL #688

Here in SoCA, I don't believe it was ever approved. The 2 or 3 times I've seen it used, it was rotted away as in the pic. One beach city here won't even allow EMT or GRC outdoors, preferring PVC. The next city south will not allow PVC aboveground, requiring GRC or EMT... Go figure