contactor / overload

[big-steve]

I'm probably going to get shot for this question, but when wiring a contactor/ overload does it matter wich side the supply is connected? I.E into the overload first or into the contactor and out through the overload?

 

[Darkwood]

Depends on the contactor overload set-up.... you can get stand alone motor overloads which are usually fitted upstream of the contactors but as I assume you refer to the O/L that fit on the out going side of the contactor then you should always bring in supply at L1,L3,L5(top) and out L2,L4,L6(bottom) note markings may vary then into overload and exit to motor as they are marked. It would work on DOL set-up although i'm not condoning it as issues arise when fault finding or example and also you would be more often than not ignoring the manufacturers instructions... also have a little think about a star/delta set up and that's where your problems really start

 

[Knobhead]

It’s the conventional way of wiring the unit. Go against that convention you could catch someone out.

 

[Marvo]

I'm not sure if a thermal overload will work auto reset mode if it's wired in reverse. I'd also say stick with convention, it makes life less complicated and less risky in the long run.

 

[Knobhead]

The O/L unit will work as normal in any direction. It's convention that wories me with this.

 

[Engineer54]

I'm not sure if a thermal overload will work auto reset mode if it's wired in reverse. I'd also say stick with convention, it makes life less complicated and less risky in the long run.

I can't see how you can mount the overload module at the top, if it's a conventional starter type unit. I doubt it would fit, and if it did, the ON/OFF control buttons would be out of place requiring, a separate button station next too the starter. If talking about a panel mounted contactor, then yes it could well be mounted at the top, but as others have wisely stated, could or will confuse others after you.


If your having a physical problem with mounting the O/L unit conventionally, rather than trying to accommodate the standard unit at the top, you can purchase stand alone O/L modules that you can mount at the side of the contactor in a panel, or if it's a conventional starter type unit, in a separate enclosure mounted next to the starter... Just all seems a lot of trouble to get around the conventional arrangement... !!!

 

[MDJ]

I'm probably going to get shot for this question, but when wiring a contactor/ overload does it matter wich side the supply is connected? I.E into the overload first or into the contactor and out through the overload?

I think it does yes, the load always gets connected to the overload and the mains into the top of the contactor, Out of interest purely for my selfish pleasure, why are you asking about this? short cables and don't want to rewire or crimp out perhaps?

 

[Knobhead]

I can't see how you can mount the overload module at the top, if it's a conventional starter type unit. I doubt it would fit, and if it did, the ON/OFF control buttons would be out of place requiring, a separate button station next too the starter. If talking about a panel mounted contactor, then yes it could well be mounted at the top, but as others have wisely stated, could or will confuse others after you.


If your having a physical problem with mounting the O/L unit conventionally, rather than trying to accommodate the standard unit at the top, you can purchase stand alone O/L modules that you can mount at the side of the contactor in a panel, or if it's a conventional starter type unit, in a separate enclosure mounted next to the starter... Just all seems a lot of trouble to get around the conventional arrangement... !!!

Not all contactor/overload arrangements are close coupled so the arrangement can get swapped around. But due to convention I wouldn’t recommend going against the norm.

 

[big-steve]

MDJ - it's just out of curiosity really I was called to a breakdown and had 2 identical pumps. Had one with the supply at the top of the din rail mounted contactor and overload and and the other had the supply going into the overload then out through the top of the contactor. And was just wandering if its bad practice

 

[Marvo]

If there two different conventions in the same panel then I'd say that was worse than just bad practice, I'd class that as needing attention.

 

[Hawk81]

In my opinion the Supply should go into the top of the contractor and the load out of the overload. If wired the other way and for some reason the overload was removed with the supply on the pins that stick out from the overload would be exposed and live making it dangerous. Where wired normally this would not be the case.

 

[Engineer54]

Not all contactor/overload arrangements are close coupled so the arrangement can get swapped around. But due to convention I wouldn’t recommend going against the norm.

That's what i was trying (badly) to explain!! lol!!

 

[big-steve]

Thanks all
Hawk I agree with that and Iv changed it around so the supply is in the top and load is from the overload. Cheers all