Greenhouse Wiring Methods

[johnsciolino]

My question is does all the wiring in a greenhouse have to be "wet location".
This is a retail greenhouse in which everything is hand watered. All the boxes below 8' are raintight and everything above is standard emt and mc cable. We used wet location light fixtures just because the standard 8' strips rust like crazy.

 

[tom baker]

Re: Greenhouse Wiring Methods

Does it meet the definition of a wet location:
Location, Wet. Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

My call would be its a wet location.

 

[peter d]

Re: Greenhouse Wiring Methods

I would certainly call it a wet location myself. Personally, I would only use PVC and LNMFC in a greenhouse. EMT may look nice in the beginning but it will rust eventually, and even the most diligently sealed aluminum die-cast boxes have a way of turning into dust after a while.

 

[physis]

Re: Greenhouse Wiring Methods

I think whethrer a green house is a wet or damp location would depend on which green house you're talking about.

But I completely agree with Peter on using plastic. I think the fertilizers cause reactions with metals too.

 

[petersonra]

Re: Greenhouse Wiring Methods

My call is that it is not a wet location. There is no reason to believe that someone will hose down the electrical equipment just because they have a hose in the greenhouse.

OTOH, it is a humid area and rust is likely if metallic fittings are used. I'd be inclined to use PVC.

 

[johnsciolino]

Re: Greenhouse Wiring Methods

By definition its a damp location. The manufacture of the greenhose does not recommend PVC due to the heat. Even though PVC is sunlight resistant, we all know what happens several years down the road in this enviroment. Also the structural beam spacing would not provide the required support for PVC. We used EMT homeruns above 8' with standard boxes and MC whips for motors and lights. The lights are vaporproof only because of the rust issue with the thin metal.