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Hazardous Area Flexible Coupling Uses

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elfman

Mechanical
Oct 21, 2003
79
We have a product that removes debris from raw sewage. Essentially it is a drum screen enclosed in a large, enclosed tank. The tank has covers to help contain the nasty sewer gases, liquids and wash spray that will be present as part of the process. In the past the drive motor ~1HP, 3phase, 480VAC (typical) has been located outside the tank in open air. Recently, I believe for cost reduction purposes - moved the motor inside the tank. I was then asked how to route the cable into the tank. It was an 8 conductor cable (3 phases, ground, (2) conductors for thermostats, (2) for anti-condensation heater). The cable was rated for Class 1, Division 1 dry service - not for use inside tank where it will be wet 24/7. The motor mount has been designed to allow for the motor to be swung out of the tank for maintenance purposes. I have found a Class 1, Division 1 wet service rated cable, but only in 4 conductors, so now I have to get a little more creative in how we get two cables into the motor j-box - not a problem. I think I have that figured out.

The issue I am facing is there are those who want to use a flexible coupling such as an Appleton EXGJH type. I have seen these used in multiple locations and I agree that they are relatively flexible, but where the motor will be rotated at least 90° on a regular maintanence basis, should something like this be used or a SO type cable rated for the location? Give me some thoughts and concerns - I have a lot myself and am trying to find related documentation so we can provide a good and safe product that meets code.

Thanks much in advance.

"To be or not to be, that is the question" - William Shakespeare via Hamlet
 
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I don't know exactly what the disposable space in the enclosing tank is. However, in my opinion,you may use 2 cables-one for power and one for control-in a rigid conduit up to a position close to the motor and from here to use a flexible connection-like AppltonEXGJH or else. One or two hazardous location [class 1 div.1] junction boxes you could use in order to complete the connection.
By the way, we don't use hazardous location cables but only hazardous location appurtenances [rigid conduits, junction boxes, flexible conduits, sealing units and so on].

 
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