I'm sure it can, but it probably shouldn't be.  Should or should not is a much more important than can or can not.  If there is a "top" indicated anywhere in the installation instructions then that is exactly how it must be installed to retain its listing.  But even beyond that the first person that has to work on it will gather want to strangle you.

I would anticipate problems with electrical inspectors if you are talking about doing this in the US.  If this is an engineered product, it was probably designed and tested to be mounted in a certain orientation and the heat rise and temp ratings would be based on this.  

If you insist, I'd recommend using a cover that can be completely removed rather than a hinged door.  

I'd try to find another solution, regardless of what the perceived problem is.   

David Castor
www.cvoes.com

There's so much information missing from your question, it makes it very difficult to give a good answer.  What's in the cabinet?  How big is the cabinet?  What is the environment like around the cabinet?

I agree that it's probably okay (technically) to do it, but it could also be a huge liability safety-wise.  People and tools could possibly fall into the cabinet and cause a fault, or be electrocuted.  It could fill with water or debris.  People could rest things on the lid, deforming the cabinet or making it a maintenance headache to get it open again.

Please don't misread my statement.  The "can" part deals with the possibility that it could physically be installed that way, making no value judgment (yes, it can - it is physically possible to do so - be installed that way).  The "should" part takes on the value judgment (no, it should not be installed that way).  Many things can be done that shouldn't be done.

Thanks for the responses.  I did not feel comfortable suggesting a varience in cabinet orientation- however, I could not find anything in the code that said it "couldn't" be installed in an alternate position either.  Thanks again!