NEMA Type 1 or UL Type 1 enclosure VFD?

[ozmosis]

This is really aimed at the experts in the US.
Working for a large European drives manufacturer, I can read the various explanations of what constitutes a NEMA 1 and a UL type 1 enclosure (this is around a VFD by the way). However, after numerous discussions with our teams in the US, I still cannot get to the bottom of what is required in the US market. It appears that you can offer a NEMA 1 enclosure or a UL Type 1 enclosure. However, I’m interested in gaining views from those who may specify or use VFD’s in the US and ask what is actually required?

 

[DickDV]

Basically, nothing is "required". It depends on the application.

For drives mounted in enclosures, open construction is OK.

For drives mounted by themselves and exposed to casual contact, NEMA 1 or UL Type 1 (I am quite sure these are the same spec) is required. This spec required primarily that contact with energized circuits by fingers, critters, prying minds, etc. by prevented. Air and therefore dust and moisture is not prevented from entering. NEMA 1 is also NOT an outdoor rating. For that you need NEMA 3 with its various subclasses.

NEMA 12 is a sealed enclosure against dust and moisture but not water under pressure. NEMA 4 includes water under pressure.

 

[rbulsara]

In the USA, the enclosures typically meet the specs of NEMA.

NEMA 1 enclosures are for indoor, dry location application.
Someone may direct to you a complete list of NEMA ratings for enclosures.

UL listing ensures some level of safety while using the equipment. It is entirely probable that you have to have a NEMA rated enclosure (suitable the application) to even get an UL listing. So in general you need both. There are other testing agencies, such as ETL who will test an assembly to UL standards and may be acceptable to most jurisdictions.

Where many things are not 'required', it is very important that you meet most widely accepted practices otherwise you are exposing yourself to risk of undue litigation and headaches, specially in the USA.

 

[buzzp]

This is the minimum rating. Any reputable manufacturer should meet this with ease. UL tests to NEMA standards as well, believe its UL50. UL, also approves electrical for safety, including enclosures, as their normal UL approvals, although they may not perform all the required "enclosure" tests needed for NEMA approval (hose down, etc) as normal testing.