ATEX vs UL and Zone vs Class/Div

kchap

Member
I have an OEM customer who has been using a Honeywell explosion proof safety limit switch on a machine rated for use in Class I Division 1 Hazardous Locations. The customer projects several sales of this machine in the coming months, but they have hit a snag with the Honeywell switch because Honeywell moved their manufacturing to Mexico, apparently without notifying their distributors, and this has resulted in a 20-week lead time for the switch.

The customer has asked me to identify alternative switches, but I have not been able to find anything comparable that is certified to North American standards. All the alternatives I have found have only ATEX certficiation for use in Zone rated environments.

Can anyone here direct me to a document that addresses the use of ATEX certified components in North America? Also, I am looking for clarification on whether or not it is acceptable to use Zone rated hardware in a Class/Div application.

Thanks!
 

kchap

Member
I found the answer to my second question regarding Zone rated equipment in a Class/Div location in section 501.5 of NFPA 70. The wording "listed and marked" there leads me to think ATEX certified equipment is not acceptable unless it also has a listing status with a NRTL.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Be careful. There is stuff that is labeled a text and for particular zones that is okay for use in Europe and other places that use the European system but the classification of the devices in the US is a little different. It needs to have a little a in front of the descriptor like a e e x, instead of just e e x. The a signifies it is a US standard component for use in US zones.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Be careful. There is stuff that is labeled a text and for particular zones that is okay for use in Europe and other places that use the European system but the classification of the devices in the US is a little different. It needs to have a little a in front of the descriptor like a e e x, instead of just e e x. The a signifies it is a US standard component for use in US zones.
Actually it needs a capital "A".
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
ATEX is meaningless in US domestic use. This is especially true where FedOSHA and most StateOSHAs have any jurisdiction.
 

paulengr

Senior Member
Generally hazardous location equipment is tested (NRTL) by FM Global rather than UL. They do most fuel train components.

NEC allows EITHER zone or class/division but they are not directly compatible. They are defined outside NEC. NEC just lays down rules on installations.

Suggest looking at common suppliers. Honeywell is one. But so is Fives, Beck (actuators), ASCO, Maxxon, Mercoid. FM might maintain a list (shopping list).

Generally we have a couple extra categories of protection methods not used by IEC.
 
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