Using AC Breakers for DC

Ricky_nz

10 kW
Joined
Aug 15, 2010
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New Zealand
I was looking at some information for some commonly used (in NZ mains panels) Schneider din rail breakers and the following information caught my eye
breakers-dc.png

This implies a relatively cheap source of breakers for common ebike voltages.
The C60N is available in 1, 2 and 3 poll (There is actually one of these in my new mains panel).
So by using polls in series they are apparently rated for DC at various voltage levels.
It looks like 1 poll for 48V or less bikes and 2 for up to 125VDC
There is an overrating factor so they trip at a different current for DC but that can easily be accommodated.

In the same document they also show how to calculate the breaking capacity based on the battery impedance pretty simple maths but nice they spell it out.
I might try one at on my bike some point but too many other things going ion at the moment. I would need to put it in a waterproof container.

Looks like they are capable of breaking 10 - 20KA or more depending of breaker and voltage/number of poles used but this is sufficiently high enough that they might be quite good in combination with LIPO as I think that it could easily handle LIPOs short circuit current.

The C120 Range may be even better as they go up to higher currents but probably with higher cost.

I would only do this with breakers where the manufacturer provides information that its ok such as above. I note they don't list the C60A breakers that are also in my panel so I would definitly goand get the C60N version.
 
Most 480v ac breakers are rated at 250v DC also. If you find some that are afforable let us know. I find fuses are easier to deal with in my assembly process (or automotive resetable fuses).
 
Sorry I didn't reply sooner, I've been very busy finishing off my new kitchen so ebikes had taken a back seat for a while.

I was thinking they might be quite handy on my workbench when testing the controller I'm developing but also as a convenient off switch.
The table above does show that there is a significant drop in voltage rating for DC on the more common breakers but easially solved by the 3 pole ones used for 400V 3 phase with the poles wired in series.
Since these 230V AC breakers are common (at least in new zealand and probably aussie too (same wiring rules basically) I assume they are cheap. I will look into it when I get a chance. I presume the single pole ones will be pretty cheap but they are only good for 48V but then again if you want to run high power / high power setups expect to pay more for protection / switching.

For those in other countries it might be worth checking the data sheets of the common breakers used locally.
I'm guessing the 480V ones you mention are pretty expensive?

I'm trying to stay away from the automotive stuff as I want stuff that I have read a datasheet that states that its ok for how i want to use it >75V etc.
Maybe if others find any information on common cheap breakers specified for DC they could put them in this thread to get a list.
 
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