class 1 div 1 flexible cord or coupling

[Aug720]

Hello,
I am working in a chemical factory in there mixing room. The room has been classified as a class 1 div 2 location. With this classification the township has decided to make 5 ft around the mixing tanks a class 1 div 1 location. My question is can I use flexible cord from my explosionproof junction box to wire my mixing motor that is in the class 1 div 1 location.?
The mixer itself will stay in the tank and is hardwired.

 

[rbalex]

...can I use flexible cord from my explosionproof junction box to wire my mixing motor that is in the class 1 div 1 location.?

No, this would not be a recognized wiring method for fixed equipment in Section 501.10(A)(1) of the 2005 NEC. Section 501.10(A)(2) permits flexible cord is very limited applications. What you have described is not one of them.

Depending on the room's ventilation and other process considerations, the township may have over-classified the location. I can't tell without a much more detailed description. The Division 1 classification has an additional consequence of extra seals at the Division 1/Division 2 boundary and it requires that the mixer motor be explosionproof as well.

 

[Aug720]

"The Division 1 classification has an additional consequence of extra seals at the Division 1/Division 2 boundary and it requires that the mixer motor be explosionproof as well."
Can you tell me what section it states this in?
Thanks,
Aug720

 

[petersonra]

Last time I looked it was impossible to get a listed cable seal, so the "legality" of the use of any cable is in doubt in my mind.

The manufacturers told me that UL refuses to list any cable seal because the cable cannot be replaced in the event of damage.

 

[rbalex]

Moved to correct response location

 

[rbalex]

As a matter of fact, there are listed seals for type MC-HL cables; however specific application listing is not an NEC requirement. See 501.140(B), especially 501.140(B)(5). The only requirement is the seal must be listed for the location – not necessarily the application [501.105(C)(1)]

UL isn't the expert in this case and the Code doesn't belong to them. Unfortunately it also leaves inspectors in the position of having to recognize a “suitable” seal and most aren’t qualified to do so. That leaves engineers and installers with an almost impossible situation when one of the conditions in 501.140(A) appears.

This was however the deliberate position of CMP 14 during the 2002 cycle where we went through Chapter 5 and selected where we wanted to specifically use the terms “listed,” “identified,” or “approved” or some other term.

 

[rbalex]

All citations are from the 2005 NEC.

• Cords only have limited uses in classified locations. See 501.140(A). None of them are consistent with the OP.
• In general, if there is a Division 1 there is a Division 2. [500.5(B)(2)(30] Raceway seals are required at each boundary [501.105(A)(4) and 501.105(B)(2)]
• All motors in Division 1 must be explosion-proof or one of several other constructions not economically justified for the OP application. [501.125(A)] Three phase motors in Division 2 may be general purpose.

My personal opinion is most electrical area classification is done from a position of ignorance and over classification,? just to be safe? is the common result. It usually leads to impossible conditions or unnecessarily expensive constructions.

 

[petersonra]

Hi Bob.

I was thinking about this and recall vaguely running across a case something like this where a vat of some type had a paddle mixer. I seem to recall they mounted the motor on a long shaft some distance (maybe ten feet) above the vat so they did not need an XP motor.

 

[rbalex]

Yes, that is common practice.

It is just that the OP described the entire facility as Division 1 so the shaft length would, in this case, be irrelevant.

In all likelihood, the facility is overclassified. (Which is also common)

 

[ed_man]

Maybe I misunderstood the question but... 501.140 states the following. "Flexible Cords, Class I, Divisions 1 and 2." "Permitted Uses. Flexible cord shall be permitted:" "For electric mixers intended for travel into and out of open-type mixing tanks or vats."

Does this not allow the use of flexible cords?

 

[rbalex]

I do believe you misread it. The last sentence in the OP indicated the mixer was fixed. (The mixer itself will stay in the tank and is hardwired.).

 

[ed_man]

oops... you are correct.

 

[alaskanoilelectrician]

Class I Div I flexible cords

Class I Div I flexible cords

Funny thing your discussing this topic ....I'll tell you what I have found out in the past few days in regards to this topic.
First of all in my opinion if it has been classified as Class I Div I the typeof of cable used must be approved for use as such.
The type of flexible cable that you should use in my opinion would be MCHL.
MCHL stands for Metal Clad Hazardous Location.....The type of connector that I've used here on the North Slope is called a TMCX I think Crouse Hinds makes it.....TMCX stands for terminator metal clad .......X stands for explosion
proof.......quite common up here.....Vinyl jacket over a continuously welded corrigated armor.....we use aluminium armor....but they have steel also....
up here the conductors are xhhw-2 also....in the teminator kit comes packing material for the connector......it's a two part compound that you kneed with you hands and has a short working time before it starts to harden.
Now back to the flexible cord issue you have.....I have recently did some investigating into this .......Darn, the web site info i was to give you I left it at work....anyway.....the flexible cord some outfits are using is a shipboard marine cable with a bronze armor. You also need special connectors...something like a CGB but it also has a packing sealing compond that you install.........None of this is very complicated you get the hang of it after installing 15-20......They need to be installed correctly......
Now this Marine cable has not been UL approved yet for Hazardous Locations but they do use it in canada.....Notice canada with no capital c.........they dont deserve a capital c in my book.......anyway I spoke with a electrical whole saler yesterday and he says the name of a approved flexible cord for this use is call boss rig cable.......rig for a oil drilling rig.......He hasnt sent be the litature on it though......
anyway you dont have a temp. installation or mobile machinery either. so none of this matters anyway....by the way where in the heck is the spell check??????????????????!!!!!!!!!!!!!!!!!!!!