Explosion Proof Motors

petersonra

Senior Member
do you need an EY seal fitting then?
I don't know. Some devices are factory sealed, but you still sometimes need a seal downstream.

I don't know what you mean by potted either. What exactly do the instructions that came with the motor say? Does it says it is factory sealed? Or does it say potted? I can't recall ever seeing the word potted in the factory manual for an XP motor, but maybe I missed it.
 

tkb

Senior Member
Location
MA
I don't think I have ever used an EY when connecting to a C1D1 motor.
They aren't an arcing device and I don't think one is required.
 

rbalex

Moderator
Staff member
A typical explosionproof motor has a (potted) factory seal between the motor terminal box and the rotor enclosure. A few, especially small single-phase motors, may have a terminal box that is integral to the rotor enclosure and may not have an factory seal. This is not particularly common. In any case, a NEMA explosionproof motor will indicate on the nameplate whether it is factory sealed or not.

For facory-sealed motors an external seal is only required at the motor terminal box where the raceway entry is 2 inches or greater. [Section 501.15(A)(1)(2)]
 

kwired

Electron manager
Location
NE Nebraska
I don't think I have ever used an EY when connecting to a C1D1 motor.
They aren't an arcing device and I don't think one is required.
A capacitor start motor would have a contact to open the start capacitor circuit, but could still be sealed and require no additional sealing. One needs to look at motor information to know for certain.

You still need a boundary seal at some point.
 

tkb

Senior Member
Location
MA
I should add that all of the motors I have connected were sealed. I can't remember ever seeing an unsealed C1D1 motor.
 

rey-man

Senior Member
Location
New york
The motor does not say if it is factory sealed but the catalog sheet says the leads are potted.

So does potted means it is sealed?
 

petersonra

Senior Member
I'd like to see the catalog cut.
I cannot remember ever seeing that word used on an XP motor.

I have seen it on motors intended to be submerged though.

but it is not like I have looked real closely at XP motor spec sheets all that much.

ETA: So I went and looked at a Baldor XP motor cut sheet. Guess what? It uses the word "potted" to describe the seal between the junction box and the motor.
 

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rbalex

Moderator
Staff member
I cannot remember ever seeing that word used on an XP motor.

I have seen it on motors intended to be submerged though.

but it is not like I have looked real closely at XP motor spec sheets all that much.

ETA: So I went and looked at a Baldor XP motor cut sheet. Guess what? It uses the word "potted" to describe the seal between the junction box and the motor.
"Potted" basically means "contained"; as in a potential explosion would be contained in the motor enclosure. It isn't commonly used, but it isn't improper either. I'm more concerned that there isn't a nameplate or label on the motor enclosure indicating it is factory sealed.
 

GoldDigger

Moderator
Staff member
To me "potted" refers to being totally covered by some sort of potting compound which may or may not be enclosed in a sealing chamber (pot). AFAIK the potting compound could be hardening, like epoxy, or flexible like putty.
In a different context you will see references to electronics which is potted, but sitting loose as a lump in a larger enclosure.
 

tkb

Senior Member
Location
MA
You can indeed see the "potting" easily enough, but can you tell visually if it is sufficient for a factory seal.
To be honest, I never gave it any thought. I guess it's always been an assumption.
 

rbalex

Moderator
Staff member
pics of the nameplates on the peckerhead and the motor. no indication it is factory sealed.

also the catalog sheet shared by our colleague is the cat. sheet for the motor we are using.

thanks.
So why would you believe it is? As I mentioned to tkb above, while you can see the "potting", can you tell if it is a sufficient seal without a manufacturer's marked certification?

Marking for "factory sealing" is a product standard, not an NEC requirement. Since I no longer have access to either the detailed NEMA MG-1 or ANSI/UL 674 Standards, I am responding by memory only.

Baldor/Reliance is a well respected motor manufacturer. In fact, it is a voting member of the NEMA MG-1 Standard committee. If their cut sheet said the product was "factory sealed", I would tend to believe it. As it is, the product is only certified for "Class I", which I also believe.

What I see from the nameplates, is an explosionproof motor that is NOT identified as "factory sealed" and is only suitable in Division 1 with an external seal at the motor terminal box.
 

rey-man

Senior Member
Location
New york
I double-checked the cat. sheets and the website. They do say that their C1D1 motors are "built to contain an explosion inside and not propagate it into the surrounding atmosphere".
 
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