Can I Replace a 2-Pole Overload with a 3-Pole Overload?

The short answer is YES!  But it may require slight rewiring on your contactor/overload setup.  Read on...

First, what exactly is 2-Pole verses 3-Pole?  Poles simply refer to the number of power conductors, or phases in a circuit.  Typical single-phase devices use 2-poles, or 2 wires (not counting safety ground) and thus need 2-pole overload devices.  The problem is 2-pole overloads are usually not in stock, as they are not as popular as 3-pole versions.  3-Pole devices are typically used on 3-phase power, where there are 3 power conductors to switch and monitor with overload detectors.

When a supplier is out of stock on a 2-pole overload, a 3-pole version can be used in its place, if it is slightly rewired.  The trick is to pass current through the 3rd pole of the overload so that the overload senses the current on all 3 legs.  Otherwise it may trip because it thinks a phase (pole) was lost.  To do that, simply take the bottom output and wrap it around back to the 3rd leg and hook the load wire to the bottom of the 3rd leg instead of the 2nd, as shown in the drawing below:

2-Pole to 3-Pole Overload Conversion

Below is a table of Weg 2-pole overloads and the equivalent 3-pole version which can be used if the above rewiring is done:

2-Pole P/N	3-Pole P/N	Use
RW27-1D2-xxxx	RW27-1D3-xxxx	for CWM9-CWM25 contactors
RW27-2D2-xxxx	RW27-2D3-xxxx	for CWB9-CWB38 contactors
RW67-1D2-xxxx	RW67-1D3-xxxx	for CWM32-CWM40 contactors
RW67-5D2-xxxx	RW67-5D3-xxxx	for CWB40..CWB80 contactors
RW117-1D2-xxxx	RW117-1D3-xxxx	for CWM112..CWM150 contactors

 

Your can find our complete line of Weg Overloads here.

Your can fnd our complete line of Weg contactors here.