Back to the Basics on Receptacles – Part 2

In a previous post, I talked about receptacles for automation equipment.  But there are many different types of mounting when it comes to receptacles.  When picking a mounting type, it is based on preference.  Each type of mounting has its good points.  Depending on what else is inside the cabinet, might sway which mounting is preferred.

r2_1A popular mounting is front mounting.  Front mounting comes into the panel from the outside of the control cabinet and is secured with lock (jamming) nut on the inside of the cabinet and sealed with an o-ring on the outside of the cabinet (figure to the right).  The o-ring with the lock nut gives the receptacle a tight seal to keep out dust and moisture.  It is one of the easier receptacles to replace since it is installed from the outside of the cabinet.

r2_2Another mounting type is back mounting.   With a back mounting, the threads are on the connector part of the receptacle.  Back mounting is the opposite of the front mounting with the o –ring and jamming nut on the outside of the cabinet.  A back mounting receptacle takes some preplanning.  The receptacle should go into the control cabinet first to make sure there is room for the other components in the cabinet like a power source, PLC or terminals.  If the receptacle needs replaced, then it might require some of the components in the cabinet to be removed to have enough room to remove the receptacle.

r2_3Panel mounting is nice because you just screw it to the outer panel of the control cabinet.  It is easy to replace but it does add more holes to the cabinet, which creates more opportunity for dust and moisture to ingress.  It is similar to the front mounting when the time comes to replace the receptacle.

An alternative to a receptacle is a bulkhead.  If there is trouble with a receptacle, a bulkhead is a good substitute. Bulkheads do require two cordsets, one on the outside connecting to the machinery, like it would on a receptacle.  The other cordset would have flying leads to connect to terminals or a power source.  To replace a receptacle, all the conductors would need to be replaced.  Only the bulkhead would need to be replaced, all the conductors would stay in the wire way.  Like the name suggests, it does take up space with the large size and second connector, but allows for more modular replacement.


When choosing a receptacle, there are many different factors to decide upon: threading, connector size and mounting types.  If you are interested in seeing what is available in receptacles or bulkheads, click here.

Leave a Reply