over head service mast to revenue meter to PV meter to fused knife, IMC vs EMT

[byteharmony]

I had a friends electrician over today. We talked about replacing my service mast which is now bent from a tree yanking it.

He took one look at my sol ark and said, NOPE, won't take the job. Why - Too much electronics, don't want to be involved.

He loves my friend so he felt sad saying no. We talked for about an hour and about 15 minutes in I said, you've told me everything I need to know to do this job myself, he said: Exactly. We talked for another 45 minutes, he left and I wanted to share this with people here and ask the follow up here I forgot to ask him at the time.

I'll share much of what I learned and have one question at the end:

TASK: 100 AMP upgrade to 200 AMPS

1. Remove all old stuff except clamps on the wall.
2. Install new weather seal on the roof lining it up with the 2" conduit inserted temporarily (a lot like putting in a solar foot).
3. drop in new the new 2" conduit and line it up with where you want your new meter socket.
4. mount the meter socket
5. connect the conduit to the socket
6. run THHN (need at least 0/2 copper)
7. setup overhead mast head (do not connect service - ZAP)
8. connect 2nd meter with nipple and mount
9. THHN meter to meter
10. conduit and mount fused knife
11. THHN meter to knife
12. Connect service
13. conduit to LB
14. LB to inside the house
15. Add Ground rods and connect ONLY to main panel, any sub panels must be connected only to only the main panel, NOT BONDED
16. With a separate copper wire connect main panel ground to water system. Tap before the meter and after the meter.

Question: How much of this is IMC (Intermediate Metal Conduit) vs EMT (Normal) Conduit?
He said he has also used Ridged Metal Conduit as well, but it's soooo heavy, so he uses IMC.

There isn't a signficant price difference between IMC and Ridged. EMT is much cheaper.

So I'm going to guess IMC / Ridged to the meter, then EMT from there. Am I correct?

 

[timselectric]

If the service drop is supported by the masthead. The masthead must be heavy wall conduit. (IMC is fine)
Everything else can be EMT, with raintight fittings.

 

[byteharmony]

Learning so much!

Learned I'm going to need a pipe threader for the IMC / Ridgid conduit. Which one is easier to thread?

Is there a reason to go with one over the other?

I'm noticing the LB (90 degree turn part which allows for wire pulling) options at 2" are all threaded at the hardware store, no set screw or weather tight options.

Any suggestions on an LB that is weather tight that is EMT or should I just go IMC / Rigid and thread it up with Teflon.

So amazing to have electricians on this form instead of just us completely inexperienced engineers .

Thank you so much guys (okay, Tim mostly

 

[zanydroid]

I always thought threads are weather tight. You should be able to buy a RGD LB and put waterproof EMT fittings on there.

There are also a lot of specialized fittings that are not at the bigbox. Hopefully the electricians here will have brand recommendations (Arlington or South wire I think have some of these semi exotic things).

You can also have those heavy duty conduits cut and threaded for you (at supply houses?)

 

[byteharmony]

I always thought threads are weather tight. You should be able to buy a RGD LB and put waterproof EMT fittings on there.

There are also a lot of specialized fittings that are not at the bigbox. Hopefully the electricians here will have brand recommendations (Arlington or South wire I think have some of these semi exotic things).

You can also have those heavy duty conduits cut and threaded for you (at supply houses?)

This RGD pipe stuff is all new to me. Anyone who thinks they're not waterproof please let us know!!

I had a buddy mention the same thing, that the big box story doesn't have a lot of special fittings. I'm trying not to be special as much as possible with this project. Trying to learn common electrical / electrician things. With a pipe threader costing $40 - $400 getting that at a place that will cut it for you makes a lot of sense!

One more question: Should the copper wire that bonds the house water system to the main panel be a continuous chunk of copper that also bonds the ground rods or could that be separate chunks of metal bonded at the main panel buss bar?

(Added items to above list, new services will probably require grounding to come up to code)
15. Add Ground rods and connect ONLY to main panel, any sub panels must be connected only to only the main panel, NOT BONDED
16. With a separate copper wire connect main panel ground to water system. Tap before the meter and after the meter.

 

[rcrracer]

Learning so much!

Learned I'm going to need a pipe threader for the IMC / Ridgid conduit. Which one is easier to thread?

Is there a reason to go with one over the other?

I'm noticing the LB (90 degree turn part which allows for wire pulling) options at 2" are all threaded at the hardware store, no set screw or weather tight options.

Any suggestions on an LB that is weather tight that is EMT or should I just go IMC / Rigid and thread it up with Teflon.

So amazing to have electricians on this form instead of just us completely inexperienced engineers .

Thank you so much guys (okay, Tim mostly

You may be able to get away without having to thread the IMC riser. I believe 2 1/2" EMC and IMC have the same outside diameter. You might be able to use 2 1/2" IMC with a 2 1/2" EMT water tight connector. There used to be a table near the back of the NEC that showed conduit outside diameters. You may need to buy a steel one to make it look official. 2 1/2" IMC threadless connectors are probably hard to find and expensive. They are 2 1/2" mast kits if you need some parts.. Seems like there used to be 7'- 2 1/2" mast risers that were threaded on one end, to be used with a slip fit weatherhead like included in a mast kit.
Don'forget clearances over any roof and driveways. An inspector may bitch about the IMC being connected to an LB instead of a panel or a meter socket because the latter two offer a more stable support.

 

[timselectric]

Heavy wall conduit comes in ten foot lengths.
They are pre threaded on both ends, and come with a threaded coupling already on one end.
You will need the threads for the connection to the top of the meter. But the weather head at the top just clamps onto the pipe (no threads needed on this end).
Unless you are doing something other than straight up with the riser. You shouldn't need to thread anything.
Everything else can be EMT, with compression (raintight) fittings. The LB threads accept a standard EMT connector.

 

[zanydroid]

To clarify, when I said "special fitting" I meant LB with integrated raintight EMT.

You can piece this together with RGD threaded + raintight EMT, also you don't have to worry about whether you can find one with one side threaded (for the IMC/RGD side) and one side raintight EMT. You probably also gain very little from using the special fitting... it's not like you're ever going to redo or see this thing.

 

[Supervstech]

Keep in mind, you will need an offset fitting to the rigid riser. Or you will have too large a gap to mount the riser to the house.

Commercial Electric 2 in. Rigid Metal Conduit (RMC) Offset Nipple FRONZ-200-1 - The Home Depot

Commercial Electric's Offset Nipples are used to provide a connection between two outlet boxes or metal enclosures. Offset nipples offset the axis of raceways 3/4 in between enclosure runs. Often used

www.homedepot.com

And a coupling.

(Why they don't make a street version of this is beyond me...

 

[timselectric]

I only use adjustable riser clamps. So that I never have to worry about needing an offset.
I've only ever needed an offset for a 100a service riser. But that's more for the sise change than anything else.

 

[Supervstech]

The standoff clamps work well also, unless there is a weird soffit angle preventing a close fit.

 

[byteharmony]

Wow, thanks so much for all your contributions. This is really helping!

One more question: Should the copper wire that bonds the house water system to the main panel be a continuous chunk of copper? I saw a friends panel today that was not done by a licensed electrician. It just had a copper run from the panel ground bus bar to the water meter, both bonded before and after the meter. Is that code?

These are some new words for me so please help me if I get one of these definitions wrong.

you will need an offset fitting to the rigid riser

rigid riser = the pole that extends through and above my roof made of Rigid (RDG) conduit?
riser clamps = the clamps on the pole above the roof that hold the wire that is dangling from the power company pole.

I only use adjustable riser clamps. So that I never have to worry about needing an offset.

If you didn't use adjustable riser clamps what would you use and what does it have to do with an offset?

I've only ever needed an offset for a 100a service riser. But that's more for the sise change than anything else.

I measured my mast pole circumference 7.5" - calculated the diameter 2.38, looked up the table mentioned above, rigid steel conduit outside diameter 2.375 = 2" rigid conduit. So that's the size of the hole in my roof.

The standoff clamps work well also, unless there is a weird soffit angle preventing a close fit.

standoff clamps and google were not kind to me. I found some that looked like they mounted to unistrut, other that seem to be a circle with a stem on it. Is it just any kind of clamp that supports the pipe a distance off the wall.

 

[timselectric]

Should the copper wire that bonds the house water system to the main panel be a continuous chunk of copper?

Yes, no junctions.

bonded before and after the meter. Is that code?

In some places it's a requirement. But, in all places it's a good idea. Newer meters are made of plastic.

rigid riser = the pole that extends through and above my roof made of Rigid (RDG) conduit?

Yes

riser clamps = the clamps on the pole above the roof that hold the wire that is dangling from the power company pole.

No
They are the heavy duty "straps" , that support the riser. Connected to the house.

If you didn't use adjustable riser clamps what would you use and what does it have to do with an offset?

Non adjustable, means that they have a fixed dimension from the house.
If this doesn't line up perfectly with the meters hub. You need an offset fitting to align the connection.

I measured my mast pole circumference 7.5" - calculated the diameter 2.38, looked up the table mentioned above, rigid steel conduit outside diameter 2.375 = 2" rigid conduit. So that's the size of the hole in my roof.

2" rigid is the standard riser.

standoff clamps and google were not kind to me. I found some that looked like they mounted to unistrut, other that seem to be a circle with a stem on it. Is it just any kind of clamp that supports the pipe a distance off the wall.

There are multiple types of riser clamps.
But they are all UL listed for the purpose.

 

[Hedges]

This RGD pipe stuff is all new to me. Anyone who thinks they're not waterproof please let us know!!

Water pipe, we use tape or dope before threading it together to make it waterproof.
Conduit has straight threads. I don't think it could be truly waterproof. Underground, assume it fills with water.

Where conduit connects to my breaker panel, it threads into "B" hub, which fits over a flange. That spill water.
Little water should run down the conduit to the threads, under the eaves, but I think I'll seal them one way or the other, so they can hold standing water. Don't want water dripping on my breakers.

 

[Supervstech]

Offset riser clamp

https://www.lowes.com/pd/Sigma-Electric-ProConnex-2-in-Conduit-Hangers-Schedule-40-PVC-Compatible-Schedule-80-PVC-Compatible-Intermediate-Metal-Conduit-Compatible-Galvanized-Rigid-Conduit-Compatible-Electrical-Metal-Tubing-Compatible-Rigid-Metal-Conduit-Compatible-Conduit-Fitting/1014037

As opposed to a two hole clamp

Rigid Pipe Strap Clamp Hanger, 2 Holes, Galvanized or PVC Pipes, IMC Conduit (10, 1-1/4 Inch) https://a.co/d/cqahur3

 

[timselectric]

Offset riser clamp

https://www.lowes.com/pd/Sigma-Electric-ProConnex-2-in-Conduit-Hangers-Schedule-40-PVC-Compatible-Schedule-80-PVC-Compatible-Intermediate-Metal-Conduit-Compatible-Galvanized-Rigid-Conduit-Compatible-Electrical-Metal-Tubing-Compatible-Rigid-Metal-Conduit-Compatible-Conduit-Fitting/1014037

As opposed to a two hole clamp

Rigid Pipe Strap Clamp Hanger, 2 Holes, Galvanized or PVC Pipes, IMC Conduit (10, 1-1/4 Inch) https://a.co/d/cqahur3

Those are just straps.
Not riser clamps.

These are what I use.

https://www.gordonelectricsupply.com/p/Arlington-615-Pipe-Supp-Clmp-With-10-In-Bolt/5901861?gad_source=1&gclid=Cj0KCQjwsp6pBhCfARIsAD3GZuaeB7FO0SR_bUBH9K-G0Ivq1xv-1tsQN4n5vX94qhkMfID09-WzumMaAlViEALw_wcB

 

[Supervstech]

Those are just straps.
Not riser clamps.

These are what I use.

https://www.gordonelectricsupply.com/p/Arlington-615-Pipe-Supp-Clmp-With-10-In-Bolt/5901861?gad_source=1&gclid=Cj0KCQjwsp6pBhCfARIsAD3GZuaeB7FO0SR_bUBH9K-G0Ivq1xv-1tsQN4n5vX94qhkMfID09-WzumMaAlViEALw_wcB

Yes, those are required if the riser is too far from a surface.

 

[timselectric]

Yes, those are required if the riser is too far from a surface.

Around here, they are required for every riser.
But maybe we are having a terminology miscommunication.
We don't call it a "riser", unless it supports the overhead utility drop. (In my area)

 

[Supervstech]

Here, any form of support is required, must be within 18" of panel, and every 4' of rise.
Plus, if the riser is more than 12" above the roofline, a guide wire support is required to the roof, for support of the service drop.