Crossy Posted July 8, 2021 Share Posted July 8, 2021 Found whilst I was actually looking for something else. What happens when you use an AC breaker on a DC circuit or you use the wrong voltage rating of DC breaker. We want you all around long enough to share your next build with us. Be sure to watch till the end if you think that new 600VDC Schneider (or other brand) charge controller install you‘re doing is no big deal safety wise… we’re talking rubber gloves or rubber bag time people, the choice is up to you. Be safe out there! 1 Link to comment Share on other sites More sharing options...
Muhendis Posted July 9, 2021 Share Posted July 9, 2021 Excellent demonstration. The reason that almost never happens with a DC breaker is down to the construction of the plastic within the breaker. When a DC breaker opens there is a BIG explosive spark from the contacts. This spark is channeled down a relatively long "tunnel" (measured in centimeters) and dissipates before it reaches the end. The spark always originates from the same electrode and is therefore easy to control. AC breakers don't have such a channel due to the randomness of the spark relative to the sine wave. If you already knew this, stop reading now. 1 Link to comment Share on other sites More sharing options...
johng Posted July 13, 2021 Share Posted July 13, 2021 Would one of those "old fashioned" knife switches be usable ? Link to comment Share on other sites More sharing options...
Daffy D Posted July 13, 2021 Share Posted July 13, 2021 (edited) Many years ago I wanted to use a DC switch on an AC circuit just to switch a Hatari fan that had fried electronics. I posted on here about the arcing problem between DC and AC switches but nobody seemed to know what I was talking about. Guess I was ahead of my time. Edited July 13, 2021 by Daffy D Correction 1 Link to comment Share on other sites More sharing options...
BritManToo Posted July 13, 2021 Share Posted July 13, 2021 I don't use any unnecessary breakers. My DC breakers are the MC4 connectors on the solar panels. My AC breaker is the plug the GTI uses to plug into the wall socket. Link to comment Share on other sites More sharing options...
Crossy Posted July 13, 2021 Author Share Posted July 13, 2021 2 hours ago, johng said: Would one of those "old fashioned" knife switches be usable ? Not that one, it's an AC version. The DC ones have a spring loaded snap action on the knives. I'll see if I can find a photo. Link to comment Share on other sites More sharing options...
Crossy Posted July 13, 2021 Author Share Posted July 13, 2021 1 hour ago, BritManToo said: My DC breakers are the MC4 connectors on the solar panels. You mean the ones marked "Do not disconnect under load"? 1 Link to comment Share on other sites More sharing options...
Crossy Posted July 13, 2021 Author Share Posted July 13, 2021 7 minutes ago, Crossy said: Not that one, it's an AC version. The DC ones have a spring loaded snap action on the knives. I'll see if I can find a photo. Not the best image, but you can see the spring loaded bit. The idea is that it snaps away quickly to break the circuit and arc. Link to comment Share on other sites More sharing options...
Muhendis Posted July 13, 2021 Share Posted July 13, 2021 This ancient DC switch gear vid shows plenty of sparks. 2 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now