Outdoor Transformer

[steve66]

I need to spec a 480V to 240V transformer that will be located outdoors.

I'm a little reluctant to use a dry type. I know they are rated 3R (with weather shields), and are frequently placed outside, but I'd like to spec something a little more rugged and waterproof.

I would spec a liquid filled transformer, but I don't know if anyone even makes those for low voltage (<1000V). Was also thinking about a epoxy encapsulated transformer, which I think is also called a cast resin xformer.

Does anyone know if they make liquid filled low voltage xformers?

Pros or cons to the epoxy or resin xformers?

thanks in advance.

 

[don_resqcapt19]

What size transformer? I have installed many dry type transformers outside with weather shields with no issues.

 

[augie47]

I too would not hesitate to use a transformer with shields but there are encapuslated transformers available in certain sizes.
ACME T3533111S is one example

 

[steve66]

In the 45 to 75 KVA range.

 

[don_resqcapt19]

In the 45 to 75 KVA range.

I don't think you will find either liquid or epoxy types in that size range.

 

[electrofelon]

One option would be to build a "dog house" around a standard dry ventilated type, if that made you sleep better at night, and it would look better. I did that recently where I used pole type transformers for a medium voltage step up step down for a long wire run. The cost and availability of pad mounts has not been great and I found some real nice new surplus pole units, and it was well worth getting those and just building a dog house on top of the transformer pad to enclose it. Similar philosophy might apply to you

 

[electrofelon]

Something like this (this is on posts not a pad).

 

[JoeStillman]

You need outdoor dry type for that size. Can you get one in NEMA 4X?

 

[steve66]

Something like this (this is on posts not a pad).

Hey, that might help keep the copper thieves away too.

I wouldn’t jump any fence with a big doghouse like that inside

 

[Strathead]

Hey, that might help keep the copper thieves away too.

I wouldn’t jump any fence with a big doghouse like that inside

An aluminum wound transformer also keeps the copper thieves away also.

 

[electrofelon]

Hey, that might help keep the copper thieves away too.

I wouldn’t jump any fence with a big doghouse like that inside

 

[electrofelon]

But seriously, consider that you save the ~ $700 on a transformer pad too (if you build it on posts), then potentially thousands on the transformer, plus a nicer look, it can be a good option.

 

[jim dungar]

Depending on size, almost every major manufacturer's dry type transformers are Vacuum Pressure Impregnated epoxy making them resistant to moisture (in parts thanks to the EPA). In North America, you typically will find Cast Coil construction only in the large sizes, say 500kVA and larger.

For the most part even the heat from an unloaded energized transformer is sufficient to keep it dry, except for flooding conditions. This is why weather shields are sufficient, except they dont protect the bussing and insulators.

 

[steve66]

If there aren't really any other options in these smaller sizes, i guess a standard dry type it will be.