Grounding Metal Junction Boxes Question

[Robert11]

Hello:

Will be installing a floodlight over my deck.

Ths situation is basically -

- wires come thru the wall to the outside house wall.

- there I will have a metal weathertight box that will make a 90 degree turn to allow a run of PVC conduit upwards, about ten feet.

- then another metal weathertight box that will hold the floodlight.

Was wondering about the grounding.

Will ground the uppermost light assembly and the box via the green wire, of course.

Think it is necessary, or a code requirement, to ground the lower box also ?

It is just providing some protection for the wire nut splices of the house wires coming thru the wall, and the new wire run up inside the conduit.

Thanks, B.

[Andy Hill]

Too damn lazy to check the code book right now, but I'd ground the lower box, too. Basically, if there is a possibility that a live wire can come in contact with a chunk of metal that someone can touch, you want that metal grounded. Better a tripped breaker than new business for the morgue.

[Doug Miller]

Absolutely it is a Code requirement to ground *all* metal boxes.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[The Real Tom]

Yes, per 2002 NEC 250.148(A) to paraphrase: "equipment grounding conductor must be connected to the box via ground screw or via listed device"

hth,

tom @

[Goedjn]

If you were running the cable straight through the box, I'd have said "no, it's not worth grounding it.". But if you have a splice in the box, then there's no reason

*NOT* to ground it. You've already cut into the cable.

-Goedjn

[The Real Tom]

Curious, why wouldn't it be worth grounding?

tom

[Doug Miller]

And you'd have been wrong.

Grounding of metal boxes is a near-absolute requirement of the NEC. There are only a handful of exceptions, very narrowly defined, and this is not one of them.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[Bill]

Ok, this isn't a direct reply to your question, but... why are you using a metal j-box? Why not use a PVC j-box, then you won't have the problem of trying to figure out how to ground it.

Bill Gill

[maradcliff]

ALL metal boxes MUST be grounded by code. Why did you even ask? The cost of an extra green screw is 10 cents at most. Just wrap your bare wire (or stripped green wire) around the screw and continue it up the conduit. Why is this so hard?