Tie wire, EMT, & Steel Truss

[cmonin]

Can EMT be "secured" by being placed in the "V" of an engineered steel truss and tied down with steel tie wire? I think I know better than to suggest such a thing but I'm bidding against someone who suggested this and the difference in cost, compared to a trapeze, is significant. But I'd rather ask the question and consult my peers! Many thanks!

 

[iwire]

In my opinion the NEC allows this and if done well can be stronger than most 'bang on' products

 

[mcclary's electrical]

I agree, and admittingly have done this myself

 

[don_resqcapt19]

Can EMT be "secured" by being placed in the "V" of an engineered steel truss and tied down with steel tie wire? I think I know better than to suggest such a thing but I'm bidding against someone who suggested this and the difference in cost, compared to a trapeze, is significant. But I'd rather ask the question and consult my peers! Many thanks!

Actually, if you run in the "V" of the truss, you only need to secure it within 3' of each conduit termination point. 358.30(B)

 

[LarryFine]

Actually, if you run in the "V" of the truss, you only need to secure it within 3' of each conduit termination point. 358.30(B)

Does 330.30(C) mean the same thing for MC?

 

[don_resqcapt19]

Does 330.30(C) mean the same thing for MC?

Yes it does.

 

[benaround]

Does 330.30(C) mean the same thing for MC?

Larry, With mc cable you are limited to a six foot span, where rmc,imc, and emt are a ten

foot span. Until today I thought this only applied to rmc and imc.

 

[infinity]

Does anyone know how 300.11(A) applies to this type of installation? Is using gravity to hold the raceway the same as securely fastened in place.

300.11 Securing and Supporting.
(A) Secured in Place. Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place. Support wires that do not provide secure support shall not be permitted as the sole support. Support wires and associated fittings that provide secure support and that are installed in addition to the ceiling grid support wires shall be permitted as the sole support. Where independent support wires are used, they shall be secured at both ends. Cables and raceways shall not be supported by ceiling grids.

 

[iwire]

Does anyone know how 300.11(A) applies to this type of installation? Is using gravity to hold the raceway the same as securely fastened in place.

You may be correct but please do not tell anyone in our are or I have a whole lot of zip ties to install. :grin:

 

[Rockyd]

Bob,

Bet it is a local AHJ thing. In Alaska, along the coast, they are earthquake support crazy (Your stuff would remain while the rest ofthe building has long since shook apart), in mainland America probably have a more realistic approach. So thinking it would be a "common sense" approach -which cannot be put to print in less than five or ten page

 

[don_resqcapt19]

Rob,
You bring up a good point. It is my opinion that a specific rule always takes precedence over general rule. The rule in Article 300 is a a general rule and the rules in the xxx.30 sections of the raceway and cable articles are specific rules. Also the specific rules also require that the raceway be supported and secured at each termination point.

 

[infinity]

Rob,
You bring up a good point. It is my opinion that a specific rule always takes precedence over general rule. The rule in Article 300 is a a general rule and the rules in the xxx.30 sections of the raceway and cable articles are specific rules. Also the specific rules also require that the raceway be supported and secured at each termination point.

You might be right, but I don't know of any wording that actually spells it out that neatly. Right or wrong I could see an inspector saying 300.11(A) must be complied with. IMO 300.11(A) really serves no clarifying purpose. In fact, as in this case, it does the exact opposite since it contradicts the specific rules you've mentioned.