Enclosure types for outside installations

[mic]

I am trying to figure out the requirements for enclosures housing motor and lighting control centers installed outside. Table 430-91 gives information about what the types mean but is there somewhere that specifies which type must be used for a particular application/location.

For example, my enclosure has drives, contactors, load center, relays, ... and can be installed in any weather conditions. The drive documentation does not address outside installation so they only specify type 12 as a minimum.

There is a debate here about whether we should be using 3, 3R, or 4. I say type 4 to protect the components from dust and water but my colleague says we only need 3R so we can drain condensation or water build-up.

I can flip a coin but I would prefer to know if there are actually clear rules.

Much appreciated,
mic

 

[iwire]

A 3R will meet code but will likely not protect your electronics from moisture in the air.

If you have any sort of moisture / humidity sensitive equipment that you want to last in outdoor environments IMO you need a NEMA 4 with a heating strip installed to keep out the moisture.

If your stuff is heat sensitive you might need a Air Conditioner unit attached to it. (These are made just for this purpose, not a 'window' AC)

It really is a matter of how sensitive the equipment is and how long you expect it to perform.

(Edit 12 to 4)

 

[celtic]

If your stuff is heat sensitive you might need a Air Conditioner unit attached to it. (These are made just for this purpose, not a 'window' AC)

So something like this is not allowed ?

 

[iwire]

So something like this is not allowed ?

Only if the trunk is full of dirt so you can ground the SDS.

By the way.....stop taking pictures of my wifes car.

 

[mic]

We have the heater installed, and when necessary we have ventilation to an "inside" area to reduce heat.

So in the end, 3R is minimum and the components dictate the rest.


Mic

 

[Mike03a3]

So something like this is not allowed ?

You SO owe me a new keyboard . . . I spewed coffee all over this one.

Mike

ROTFLMAO

 

[petersonra]

If your stuff is heat sensitive you might need a Air Conditioner unit attached to it. (These are made just for this purpose, not a 'window' AC)

It used to be real common to take a standard window A/C and do just that. Works just fine, and is much less costly than the purpose built units. A commercial grade A/C like you might see in a guard shack is quite adequate.

 

[petersonra]

I would be inclined to go NEMA4 with heater strips to reduce the chance of condensation. 3R enclosures tend to allow a lot of dust to collect inside an enclosure. There is not a whole lot of difference in price.

Drives tend to have lower ambient temperature ratings than other common control equipment. You might want to take a good look at the specs for your drives.

Direct sun can add a lot of heat load. A sun shade can reduce that load substantially as can a light colored surface or a shiny surface (like aluminum or galvanized).

For large outdoor enclosures I use aluminum huts with 1/2" foam insulation on the inside, or enclosures painted white that are also insulated.

I am trying to figure out the requirements for enclosures housing motor and lighting control centers installed outside. Table 430-91 gives information about what the types mean but is there somewhere that specifies which type must be used for a particular application/location.

For example, my enclosure has drives, contactors, load center, relays, ... and can be installed in any weather conditions. The drive documentation does not address outside installation so they only specify type 12 as a minimum.

There is a debate here about whether we should be using 3, 3R, or 4. I say type 4 to protect the components from dust and water but my colleague says we only need 3R so we can drain condensation or water build-up.

I can flip a coin but I would prefer to know if there are actually clear rules.

Much appreciated,
mic