IMC vs RSC

[BrandonMD]

Discussion came up when 3/4 RSC was unavailable on backorder for the first time in my 15 yrs as an electrician. We have never had a problem getting it. Is IMC a good alternative? None of the guys ive worked with have used it. Specs say lighter and just as strong and at about 2/3 the cost but my common sense tells me i would have seen more of it in the field by now if there wasnt some disadvantages to it. Any feed back appreciated.

 

[infinity]

IMO it a good alternative. I've been told it's much harder to bend by hand than GRC. The few times we've used it we used a machine bender.

 

[BrandonMD]

IMO it a good alternative. I've been told it's much harder to bend by hand than GRC. The few times we've used it we used a machine bender.

Thanks for the feedback! I ordered 100’ just to try out.

 

[ActionDave]

It's also harder to thread. Aluminum rigid is nice if that is an option.

 

[petersonra]

It's also harder to thread. Aluminum rigid is nice if that is an option.

I don't think I have ever seem AL conduit. It is probably a lot lighter weight.

 

[steve66]

I don't think I have ever seem AL conduit. It is probably a lot lighter weight.

haven't ran conduit in 30 years, but oh yea. Probably about 1/2 the weight. At least the small stuff was.

It weighed more like EMT than Rigid steel.

I've often allowed IMC in our spec where ever RMC was allowed.

I assumed contractors would usually take advantage of the lower cost and lighter weight, but I'm not sure i would ever know which of the two they installed just by looking at it.

 

[petersonra]

You would think if IMC is cheaper than RSC and IMC is allowed, contractors would use the more cost effective option.

 

[BrandonMD]

You would think if IMC is cheaper than RSC and IMC is allowed, contractors would use the more cost effective option.

This is what kind of blew my mind. Its not just a little savings. A 10’ stick of IMC is $19 compared to a 10’ stick of RSC at $28.

 

[paulengr]

This is what kind of blew my mind. Its not just a little savings. A 10’ stick of IMC is $19 compared to a 10’ stick of RSC at $28.

IMC is a high strength steel alloy. It is 25% stronger and 25% lighter than GRC. Aluminum conduit is RMC but it’s aluminum so it’s lighter and stronger than GRC and generally more corrosion resistant. Even though the alloy is more expensive per pound because the conduit is thinner IMC is cheaper than GRC. In fact you have to look closely to tell the difference. GRC is uncommon…few electricians realize that what they think of as “RMC” is usually IMC unless you specifically ask for GRC.

EMT is thin wall IMC. It is definitely not as strong but over about 1-1/4” it honestly doesn’t matter except you can’t thread it (compression fittings or set screw fittings only).

MC and TC-ER, even the metallic armored versions, are inferior to even EMT but both eliminate the need for an actual conduit as long as you support them either with a tray of every 3 feet. When allowed installation goes so much faster that it easily offsets the additional cost.

 

[infinity]

GRC is uncommon…few electricians realize that what they think of as “RMC” is usually IMC unless you specifically ask for GRC.

This is incorrect where I work. No one uses IMC. All of the steel galvanized conduit that we use is RMC.

 

[ActionDave]

IMC is harder to bend and twice as hard to thread as RMC. I can't imagine anyone not knowing the difference.

 

[electrofelon]

I have always

This is incorrect where I work. No one uses IMC. All of the steel galvanized conduit that we use is RMC.

I agree. There is no confusion. Some of my supply houses stock both, but most only stock RMC.