Cause of damaged DC connector

Cause of damaged DC connector

In the occasion of damaged MC4 connector(s), it is almost always caused by one of two reasons:

1. Incompatible connector types have been used together.

2. Improper crimping of the corresponding DC cable.

When the connector is , there is a crimped improperly, a large resistance occurs across the connection points, which causes heat. As DC power is constant, the heat builds up and will cause oxidation, causing more resistance. Eventually, the heat builds up to a point where it melts the plastic surrounding the metal connector. In rare cases, it can catch fire.


Example of a burnt connectors

Standards IEC 62548, IEC 62109-1 and IEC 62109-2 specify that the DC connector and socket must be from the same manufacturer and type. If different brands of plugs and sockets are used, the connection may not be made properly. Or, the inner sleeve may be pushed back into the plug body causing a poor connecting.

In case of faulty workmanship, the plug may not be properly crimped onto the cable. Below is a correctly crimped plug. Note, the correct crimping tool must be used.


 Must be solid and tight

 
 The cross sections of the crimped plugs reveal that they have been crimped by the proper tools 

 
The cross sections of the crimped plugs reveal that they have been crimped by improper tools
  

How do we know it was caused by the bad connection?

It’s easy to know that the damage will be concentrated at the point of maximum heat.

In the below example, we can clearly see that the areas just above and below the point of connection are not heat-damaged. So, the damage is exactly where the connection is which means the poor connection is the cause of the damage.


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