Conduit for exterior lighting - commercial

[Jeff Eastman]

........

[Corey Friedman]

Hello Jeff,

You do not need an LB at a raceway penetration through the roof.

The flashing is inadequate.

This is an inappropriate use of BX, MC or Greenfield (which ever one it is).

Sincerely,

Corey Friedman

[Jerry Peck]

First question: Is that flexible metal conduit or liquid tight?

If liquid tight, it should go into an LB, SLB, junction box, or even a piece of rigid conduit (rigid, intermediate, or EMT), and be properly flashed to that metal roof.

If flexible metal conduit, it does not matter ... because it wrong and needs to be replaced anyway - it is then up to them to replace it properly (with that also noted in the report).

Neither is secured properly (every 4-1/2 feet max. and within 12 inches of termination ... LB, SLB, conduits, boxes, etc.).

[Gunnar Alquist]

Jeff,

Because flexible metal conduit would allow water into the conduit as well as the building. Since it is an improper use of a material, I would think that it is a "repair" item.

A related question: Would it be OK to use metal flex outside if the conductors in the conduit were XHHW?

[John Steinke]

There are three different wiring methods that look very much alike ... but have different restrictions on their uses.

"Sealtite," or liquid tight flexible metal conduit, is certainly a nice product; trade practice would recommend it for this use ... but it is not required.

"Flex," or ordinary flexible metal conduit, is perfectly legal in a wet location (like this roof) ... IF the wire inside is listed for use in wet locations, and any exposed fittings are also listed for wet locations.

"MC," or metal clad cable, is also allowed in wet locations ... butm again, exposed fittings need to be suitable for wet locations.

"AC," or armored cable, is not allowed in wet locations.

The pics suggest that this may be MC, and this legal. Ugly, but legal.

[Jerry Peck]

"Flex," or ordinary flexible metal conduit, is perfectly legal in a wet location (like this roof) ... IF the wire inside is listed for use in wet locations, and any exposed fittings are also listed for wet locations.

It looks like flexible metal conduit to me, and your statement is only partially correct, and the part you left out is why flex should not be used on this roof in that manner.

This was my statement: "If flexible metal conduit, it does not matter ... because it wrong and needs to be replaced anyway - it is then up to them to replace it properly (with that also noted in the report)."

(bold is mine)
348.12 Uses Not Permitted.
FMC shall not be used in the following:
(1) In wet locations unless the conductors are approved for the specific conditions and the installation is such that liquid is not likely to enter raceways or enclosures to which the conduit is connected
(2) In hoistways, other than as permitted in 620.21(A)(1)
(3) In storage battery rooms
(4) In any hazardous (classified) location other than as permitted in 501.4(B) and 504.20
(5) Where exposed to materials having a deteriorating effect on the installed conductors, such as oil or gasoline
(6) Underground or embedded in poured concrete or aggregate
(7) Where subject to physical damage