Conduit Type in Electrical Rooms

[charlie b]

A contractor is asking clarification of a specification requirement. I don't like how the spec was worded, but let's ignore that for the moment. What type(s) of conduit do you use between panels inside the electrical room? Are there any types that you would not use? My view is that such rooms are not places in which a conduit could be subjected to severe physical damage. Am I wrong about that?

 

[zbang]

My view is that such rooms are not places in which a conduit could be subjected to severe physical damage.

If they are, there's a whole lotta other problems than just the conduit.

 

[infinity]

We use EMT about 99% of the time.

 

[hillbilly1]

I use EMT all the time between panels, could even use pvc, but metal looks more professional. I’m like you, I don’t see it as subject to severe physical damage other than where emerging from the slab that is not inside an enclosure.

 

[petersonra]

I think EMT is a good choice for such places. easy to bend, route, and install and more than adequate for the task.

I would not use plastic just because it sags and looks ugly after awhile.Plus there might well be a bunch of bends and PVC does not do bends real easily.

 

[bwat]

I spec EMT

I will say I've seen a good bit of RGS spec'ed, but it always seemed like it could be a 'copy-paste' from something else or just trying to keep it consistent with something else that actually needed that.

 

[tom baker]

EMT, and I would spec steel compression fittings, for most locations. As far as PVC goes, its takes a time to bend and install on surface so it looks acceptable. IMO EMT is faster to install as it does not have to be supported as often

 

[infinity]

EMT, and I would spec steel compression fittings, for most locations. As far as PVC goes, its takes a time to bend and install on surface so it looks acceptable. IMO EMT is faster to install as it does not have to be supported as often

I would hate you.

 

[hillbilly1]

K Mart is one retailer that specs compression, expensive way to wire a store. Probably one of the reasons they went belly up!

 

[Carultch]

EMT, and I would spec steel compression fittings, for most locations. As far as PVC goes, its takes a time to bend and install on surface so it looks acceptable. IMO EMT is faster to install as it does not have to be supported as often

What is the functional reason for specifying compression fittings as opposed to setscrew fittings, when in a dry indoor location? I thought these were interchangeable in application.

 

[kwired]

What is the functional reason for specifying compression fittings as opposed to setscrew fittings, when in a dry indoor location? I thought these were interchangeable in application.

There is no good reason. some will have reasons, but there is about as many pros as there is cons either way on this.

 

[Electricheaven]

EMT is the most standard but if the spec says "conduit", I'd ask if you could use EMT. EMT isnt "conduit" its tubing. RMC, IMC, and PVC are conduit

Sent from my SM-G965U using Tapatalk

 

[paulengr]

EMT has been proven to be as strong or stronger and lighter than RMC so no reason to use RMC except for niche situations like the hazardous locations rules.

Frankly cable tray has the advantage of easily handling the high wiring density and makes it much easier to maintain and update over time. Plus instead of supporting every 10 feet it normally comes in 20 foot sections but you can buy longer spans if needed. Think about it...a trapeze and two clips 20 feet apart compared to 2 clips on every conduit and a trapeze every 10 feet. Depending on the design you may or may not need to tie wrap the cable which takes a little extra time. No bending and it’s very easy to bolt sections together. The sole issue is that TC is not supposed to be run outside tray. But you can use TC-ER which most larger TC meets anyways and run outside the tray if supported every 6 feet so no stubs needed. Plus the fittings are just CGBs. This is the fastest to run and since labor costs drive pricing the best option. The sole complaint is some people like conduit “artistry” but in an electrical room functionality trumps cosmetics.

 

[tom baker]

What is the functional reason for specifying compression fittings as opposed to setscrew fittings, when in a dry indoor location? I thought these were interchangeable in application.

Hmm, well I like the look of steel compression. Set screw are actually faster to install, but I don't care the die cast, go with steel/

 

[tom baker]

Frankly cable tray has the advantage of easily handling the high wiring density and makes it much easier to maintain and update over time.

I have done a couple of jobs with cable tray. The trick is dropping out of the tray into enclosures. I don't have a lot of industrial experience, but it worked really well in a fire pump station were I went back and added fire alarm, radio and intrusion alarm. But for plain old every day wiring, EMT would be the most cost effective, but I have another option to consider, in my next post

 

[tom baker]

In all the jobs I did over 38 years, I would always use wireway, usually across the top of the equipment and rigid nipples down into the panels. The top of the panels, starters were all set at 5-6" AFF and the wireway was usually 6 -0 AFF to the top. For the control panels we put a wireway across the bottom and nippled up to the top wireway. And with wireway you don't have to derate until you get to 30 conductors.
One job was a 300 amp 480 volt service, I had a 12" x 12' x 12 ft wire way made at a enclosure shop (Charlie-Skyline Electric in Seattle) nippled down to an I line panel, size 3 starter, size 4 starter, lighting xfmr and lighting panel. The building was wired in EMT.

For a small 20 x 25 ft water treatment building, we ran 6x6 wire way near the top all the way around. Nippled down to gear, looked great and saved time. I will try and post pictures later. You can put a divider in the WW if required.

the wireway has the flexiblity of cable tray, but its more along the lines of what most electricians have worked with. I would suggest a good elevation drawing.

 

[Cow]

Hmm, well I like the look of steel compression. Set screw are actually faster to install, but I don't care the die cast, go with steel/

Nobody uses emt ss die cast fittings anymore, the suppliers don't stock them. It's all setscrew steel now, and has been for a few years.

 

[tom baker]

drawing is a small building with 100 amp service, wireway across the top.
The other is the 300 amp service, with the 12 x 12 wire way, installed in about 1995. I set the gear, nippled to the wireway, and set anchors thru the grear (by myself) There has been many adds since this picture was taken, easy to do with WW.

 

[tom baker]

Nobody uses emt ss die cast fittings anymore, the suppliers don't stock them. It's all setscrew steel now, and has been for a few years.

Good to know, my last 15 years I worked as an instrument tech, our electricians would install the service/feeders and wireway and I would run the instrumentation power/controls

 

[ActionDave]

What is the functional reason for specifying compression fittings as opposed to setscrew fittings, when in a dry indoor location? I thought these were interchangeable in application.

In my opinion and in my experience compression fittings are inferior to set screw. Set screw fittings are easier to confirm that the pipe is inserted to the proper depth, easier to tighten, easier to identify as not being tightened, and provide a better bite. I've done a ton of commercial remodels and I can promise you that compression fittings are way easier to demo out and pull apart than set screw.

The reason for specing compression fittings is so someone can say, "I'm better than you because I spec these." It shares the same crock of baloney as specing insulated throat connectors. There's no gain in safety. The double proof is that the stupid plastic falls out of the end of all but about three connectors on the whole building so every place that has them installed ends up being no different than a building with non insulated throat.