Enclosures for Class 1 Division 2 Locations

[rroark0003]

Guys,

Can a NEMA 4x enclosure be used in a class 1 division 2 location? Does mounting a standard HOA (hand,off,auto) switch in the front of this enclosure violate the NEC?

 

[rbalex]

Guys,

Can a NEMA 4x enclosure be used in a class 1 division 2 location? Does mounting a standard HOA (hand,off,auto) switch in the front of this enclosure violate the NEC?

Question 1, Yes and Question 2, Yes. See Section 501.10(B)(4) - both questions and 501.105(B)(1), question 2.
Enclosures are not always required to be explosionproof in Division 2 - but this is one of the case that it is.

 

[don_resqcapt19]

You may find it is cheaper to use a HOA with sealed contacts than it is to use an explosionproof enclosure and HOA. We typically use A/B 800H-JR4BP with an 800H-1HZ4R enclosure for this application.

 

[petersonra]

Guys,

Can a NEMA 4x enclosure be used in a class 1 division 2 location? Does mounting a standard HOA (hand,off,auto) switch in the front of this enclosure violate the NEC?

yes, and maybe.

a std HOA could probably be used if it had hermetically sealed contacts, if the enclosure was pressurized, or it was protected with barriers. it could also be put there if it was never wired to anything or had no contact blocks installed, which would not be real useful, but it could be mounted there.

 

[rroark0003]

Question 1, Yes and Question 2, Yes. See Section 501.10(B)(4) - both questions and 501.105(B)(1), question 2.
Enclosures are not always required to be explosionproof in Division 2 - but this is one of the case that it is.

If my understanding of 501.10(B)(4) and 501.105(B)(1) is correct I can use a nema 4x enclosure in a class 1 div 2 location. This enclosure can contain class 1 div 2 rated power supplies and relays. Also, I can install my HOA switch on the panel door povided that I have sealed contacts. Is this correct?

 

[weressl]

yes, and maybe.

a std HOA could probably be used if it either had hermetically sealed contacts, or if the enclosure was pressurized, or it was protected with IS barriers. it could also be put there if it was never wired to anything or had no contact blocks installed, which would not be real useful, but it could be mounted there.

If it has hermetically sealed contact, then it would no longer be 'standard', would it? I inserted couple of words into your post. Is that what you meant?

 

[petersonra]

If it has hermetically sealed contact, then it would no longer be 'standard', would it? I inserted couple of words into your post. Is that what you meant?

I think the extra words do clarify the range of options.

My point was you could use a standard operator with sealed contact blocks, not that sealed contact blocks are standard.

 

[weressl]

I think the extra words do clarify the range of options.

My point was you could use a standard operator with sealed contact blocks, not that sealed contact blocks are standard.

You are absulutely right but that is not what you wrote.

a std HOA operator could probably be used if it either had hermetically sealed contacts.

Just wanted to make sure that the OP did not think that he needs to comply with all the features you have listed, that any one of those is an acceptable option.

 

[rbalex]

If my understanding of 501.10(B)(4) and 501.105(B)(1) is correct I can use a nema 4x enclosure in a class 1 div 2 location. This enclosure can contain class 1 div 2 rated power supplies and relays. Also, I can install my HOA switch on the panel door povided that I have sealed contacts. Is this correct?

Your understanding is basically correct.

The further discussion by Don, petersonra (Bob) and weressl (Laszlo) is also useful.

My initial response was misleading because it implied the HOA needed to be explosionproof. <insert "red face" here> What the HOA and other internal components need is to be identified for Division 2. Don, Bob and Laszlo all gave good "non-explosionproof" alternatives.

It is important to understand that identified is a specifically defined term in Article 100. Within the HazLoc world, Section 500.8(A) discusses means and methods to determine suitability of identified equipment.

 

[rey-man]

Go to crouse-hinds, you can find the whole assembly. I use it all the time.