Class 1 Div 2

[rswolff001]

have a small wheeled skid....Class 1 Div2......XP enclosure with motor starter, xp motor. Motor is within 2ft of enclosure.....original wiring had a single seal at the enclosure, then xp flexible sealtight, into the motor connection box mounted on the motor (also xp).....question.....do I need a sealoff at both ends of the flexible sealtight? Actual length of the flexible may only be 18" or less.
Thanks, Bob :blink:

 

[rbalex]

The important question is whether the motor was/is required to be explosionproof; it is possible for single phase motors, not likely for three phase.

If is required, it still sounds like it is ok if? the explosionproof flexible fitting (technically it's an explosinproof flexible coupling) is less than 18".

 

[rswolff001]

XP Motor

XP Motor

Understand if the coupling is less than 18".....

Not sure I understand the first part of your reply.....are you stating a 3ph motor wouldn't need to be xp, or a 1p motor wouldn't need to be....or something else entirely? :blink:

thanks, bob

 

[rbalex]

In Class I, Division 2 motors, are not always required to be explosionproof. Most 3 phase motors aren't required to be; most single phase motors are. See Section 501.125(B)

 

[rswolff001]

Incoming

Incoming

two last questions and then I'll leave everyone alone......
Appleton motor starter on a wheeled skid......the incoming power is a cable with an Appleton plug connected to the motor started through a sealoff.......is the sealoff necessary?
second question.....I was always under the impression that all the threaded connections required sealant.....I've seen some other posts that indicate you should not seal the threads?
thanks, bob :dunce:

 

[rbalex]

A seal is required for the explosionproof? starter.

Conduit sealant is neither required nor prohibited, but I don't recommend it if it is installed as required by Section 500.8(E).

 

[rswolff001]

XP

XP

Yes....its an Appleton XP starter.....I was under the impression (most likely false) that the sealoff was to prevent an explosive front from propagating down through a conduit run (or out of a classified area)....not to prevent vapors from entering the enclosure itself....since there is no conduit I simply posed the question....and I will read sections you referenced in your replies this weekend.

Many Thanks,

 

[rbalex]

Yes....its an Appleton XP starter.....I was under the impression (most likely false) that the sealoff was to prevent an explosive front from propagating down through a conduit run (or out of a classified area)....not to prevent vapors from entering the enclosure itself....since there is no conduit I simply posed the question....and I will read sections you referenced in your replies this weekend.

Many Thanks,

Your impression is correct. The seal is to prevent an explosive front from propagating down through a conduit run from an explosion initiated in the starter. Explosionproof (Type 7) enclosures "breathe" and it is not unusual for gasses and vapors to concentrate in them.

In fact, seals don't prevent the entry of Class I flammable materials either. This bit of information should be in Section 501.15(C); however it is found in the last sentences of 501.15(E)(2) and (3). This is especially bad since no one has ever manufactured a 501.15(E)(2) cable.

 

[rswolff001]

One last (really) question

One last (really) question

Same application.....coming out of the motor control we have a cord with an XP plug....there is a sealoff at the motor control that the cord will pass thru.....is there a specific type of cord grip on the outgoing (cable side) of the sealoff that needs to be used.....I can't find a specific reference to it but bear with me....I only learned to read recently.......
thanks, bob:blink:

and to understand what someone has said....it always helps if they understand what they wanted to say in the first place..........

 

[rbalex]

The "fundamentals" of flexible cords is found in Section 501.140. Of particular interest to you will be Subsections 501.140(A), 501.140(B)(3)-(5).

 

[rswolff001]

still not clear....duh....

still not clear....duh....

yes I've read those sections....they seem to indicate how cables would enter xp enclosures, lighting fixtures, etc. In this case, its already been indicated that I needed a sealoff at each entry into the controller.....the cable itself will have its conductors sealed, either in the sealoff or just past the seal....so the cable gland is not actually sealing the cable, or sealing an entry into an enclosure, only acting as a strain relief.....so again...I don't find anything in the code that specifically addresses this...so do I need a specific type of cable gland....does it need an woven extension? does it need to be rated C1D2?
Thanks, Bob :dunce:


better to have embraced your stupidity and looked for assistance than to believe you are intelligent and found out you are truly stupid..........

 

[rbalex]

I'm out of the office. If I don't answer you well enough now, it may take a while.

The "key" is making sure there is no stress on terminals. Anything that does that while addressing 501.15(E) and 501.140 should be suitable. [500.8(A)].

 

[rswolff001]

Seals

Seals

many thanks.....its what I expected......just wasn't sure if there was some line or paragraph hidden away that I hadn't read that would indicate otherwise.......you have been very helpful.......I greatly appreciate you sharing your time, knowledge and experience.

Thanks, Bob

 

[rswolff001]

revisit

revisit

looks like I have a couple more questions......these seem to be out of the realm of my electrician....in the Appleton enclosure there are two grounding screws, one for incoming and one for outgoing. The incoming screw was so corroded that it could not be tightened. The lower screw was also corroded but the previous install (we were actually refurbishing three of these units) had a short wire which was wire-nutted to the outgoing motor ground. So we wire-nutted a short wire to the incoming ground, and then added the other end of the extension to the lower wire-nutted connections. I already informed the client this was not satisfactory but I have following questions.

One, is this even valid. I cannot find any reference in the code indicating its not but I could have easily missed something in the grounding section. (or classified sections)

Two, would it be legal to drill a hole and tap it in the Appleton enclosure?. Again, no one I know has ever even considered this, and I find no direct mention in the code that might negate this.

Any help appreciated as always.

thanks, bob :blink:

 

[rswolff001]

drilling

drilling

already found a prior post of yours indicating it is not acceptable (for the most part) to modify an XP enclosure unless specified by the manufacturer. I probably would not have been prone to this for liability issues in any case.

Still unclear as to the ground we installed. As I mentioned, I have already indicated to the client this was not acceptable and needed to be addressed properly. I would still like to know if it was a legal method of installing the ground wire.

Thanks, bob :blink:

 

[rbalex]

Field drilling/tapping an explosionproof enclosure just isn't a good idea - at least not without close guidance from the manufacturer. I confess I've sent a few enclosures to a qualified shop, but never had the field do it.

I have no serious problem wire nutting the EGCs together as long as they are properly sized and enclosure is properly bonded to them.

 

[goodoboy]

have a small wheeled skid....Class 1 Div2......XP enclosure with motor starter, xp motor. Motor is within 2ft of enclosure.....original wiring had a single seal at the enclosure, then xp flexible sealtight, into the motor connection box mounted on the motor (also xp).....question.....do I need a sealoff at both ends of the flexible sealtight? Actual length of the flexible may only be 18" or less.
Thanks, Bob :blink:

Hello rswolff001,

I am still learning whats required when have equipment in Class 1 Div 2, I am fairly new to protection method for Class 1 Div 2.

Can you explain why you need XP enclosure for the motor started and motor? Maybe simple question for others, but I am still learning.

Thank you

 

[rswolff001]

XP Enclosure

XP Enclosure

thanks.....I also am not comfortable drilling into the enclosure.....I have contacted Appleton and while they seem to indicate its possible, its probably not practical as I would need documentation stating they accept the modification, and I'm guessing that would be difficult at best to obtain.

As for the grounding, I was concerned because it was an XP enclosure. While I've seen this done in the field, I personally have never wire nutted any of my grounds in an industrial environment. Simply not good practice as far as I'm concerned.

Thanks again for your answers. I normally am not in the position of wiring xp devices. The electrician I would normally use was not available, but also was not familiar with some of the answers (he had always put sealer on the threaded connections and presumed it was necessary) I have always figured if I wasn't sure ask someone who was.
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In answer to the other posters query I would recommend reading NEC 500 and 502 for starters.