Power Switching Under Load

[Pink7]

Lately I seen more warnings related to switch power with breakers under load so i thought I would start a discussion on this. I use my breakers to close down system at times and never thought of that as an issue. Whats your thoughts and experience on this?

 

Pink

[lom]

Breakers are intended to switch on or off a load and the only thing you have to worry about is that the load is not greater than what the switch is rated for and that is especially important when it comes to the in-rush current of an inductive load.

Is there something special you are thinking on?

 

[Pink7]

4 minutes ago, lom said:

Breakers are intended to switch on or off a load and the only thing you have to worry about is that the load is not greater than what the switch is rated for and that is especially important when it comes to the in-rush current of an inductive load.

Is there something special you are thinking on?

 

 

I just seen warning several times last days like: No switching under load, stated very clearly. So I wanted to check what others here have to say about this.

 

Pink

[Crossy]

10 hours ago, Pink7 said:

I just seen warning several times last days like: No switching under load, stated very clearly. So I wanted to check what others here have to say about this.

 

What's the actual scenario?

DC or AC breakers? (or AC breakers on a DC source - naughty)

Are the warnings from the manufacturer or on an internet forum?

 

If you can remove the load there's little doubt that switching "cold" can improve the life of the contacts (particularly of DC breakers), but I doubt the occasional switch under load is going to do much harm (I'm assuming decent quality breakers here).

 

The issue with DC is that the arc, which should be extinguished in a properly designed DC breaker, is maintained with the breaker "off", this is not a good thing.

 

[Pink7]

2 hours ago, Crossy said:

 

What's the actual scenario?

DC or AC breakers? (or AC breakers on a DC source - naughty)

Are the warnings from the manufacturer or on an internet forum?

 

If you can remove the load there's little doubt that switching "cold" can improve the life of the contacts (particularly of DC breakers), but I doubt the occasional switch under load is going to do much harm (I'm assuming decent quality breakers here).

 

The issue with DC is that the arc, which should be extinguished in a properly designed DC breaker, is maintained with the breaker "off", this is not a good thing.

 

I see more warnings lately on the largest solar forum related to DC breakers to not switch under load. Anyway Im switch when i need even load or no load and have never thought of it as any issue.

 

Pink