Ex Motors

The feature with hazardous area motors is that they are 'type tested', i.e. the motor has been tested at an accredited testing agency and certified according to its type and the manufacturer's quality control procedures relating to its manufacturer. A potential problem arises if a motor is repaired 'in the field', as it were, and in so doing its structure is changed in such a way that takes it outside the original equipment manufacturer's [OEM] specifications.

For example, an Ex'd' motor is reassembled in such a way that its flame path is compromised. An internal spark sets off an internal explosion that is no longer contained within it, and the flame spreads to the outside, causing a major plant fire. Who is liable for the damage? The plant operator will blame the OEM. Upon investigation, the OEM finds that the motor has not been assembled correctly and notifies the operator's insurer, who refuses to pay out the operator's insurance claim. It's a good basis for a major court battle.

Any type of equipment for use in hazardous areas, whether the North American Class and Division or the IEC Class and Zone classification, needs to be evaluated and approved by an accredited agency. This applies to both manufacturers and repair facilities. As the previous article pointed out, there are serious liability issues involved if a non-accredited agency repairs equipment. Hazardous Locations equipment undergo tests and evaluations that far exceed those for equipment used in non-hazardous areas. This is not something that should be attempted by anyone without very specific training and experience. If one looks into the types of protection used under the Ex scheme, explosion-proof, intrinsic safety, purged, along with the different T-code and IP testing, one would soon discover the complexity and realize that this is not like reading a Dummy's Guide to Field Repair.

Well put.