Why did my circit breaker pop?

[bf514921]

In the picture you show the plug does not have "4 wire." What that shows is called three conductor with a ground. What is called "4 wire" or four conductor with a ground would have a red, black, white, green, and a bare ground wire.

yes, my mistake. its 10/3 romex, 3 sheathed wires and a ground. now i am confused.
I read the link. it sounds like 10/3 romex is just fine. the link did suggest 8/3. the picture was to illustrate i had 3 prong befoer and the ground wire was thier.
then agin i am no expert. just a guy trying to make beer without electrocuting himself

 

[mattd2]

First off I am a mechanical engineer so I will no doubt say something awfully stupid in regards to those electron things, But if you are running a 4500W element with 240V would this be 18.75A, and if you assume it is 240 +/- 10% (don't know how stable the power supply is - stupid #1?)this could even be 20.8A. Also what about the inrush current when the element turns on (does inrush current apply to this sort of load - stupid #2?), which is why you generally go for a slow blow fuse right?
And big stupid comment #3 coming up right here ---> have you considered going with a higher rated fuse for the element, 20A I would think would be just cutting it at best (see above), I thought fuses were there to protect if there was a short (i.e. much more current than normal). Take this with a mountain of salt and difinately get someone to confirm this first.
Matt

 

[Photopilot]

have you considered going with a higher rated fuse for the element, 20A I would think would be just cutting it at best (see above), I thought fuses were there to protect if there was a short (i.e. much more current than normal).
Matt

Thanks Matt for the suggestions but I believe a fuse or CB is there to protect the wires from overheating. If you have a sensitive item like PID you put a fuse to protect the item itself.

As far as oversizing a wire, I believe it is required for continuous load greater than 3 hours. Not sure but I read that on the internet, so it must be true. Also someone suggested a fast burn fuse is not the reason for my popped CB. Slow blow would be better but not the reason for consistent popping of the CB, I am unable to find any slow blow in 20A.

I am going to run some more continuity tests tonight inside the panel.

Heres another question. I am not sure but I think when I did my test last weekend. I think the fuse blew, the GFCI blew and the CB in the wall blew, each time. My thinking is one of these blowing would prevent the other ones from blowing. Any suggestions?

 

[Marsdude]

When faced with a electrical problem like this if I can't find an obvious answer I usually just unhook everything then, starting at the power source, start hooking things back up until I get my fault.

In your case, if you have not done all this already, I would unhook the feeds coming out of the GFI breakers, turn the GFI breaker on and power them. If everything is ok, then hook up the next component and turn the power on.Keep on doing this until you find your fault.

 

[Photopilot]

I tested the panel and found the problem. I had the double pole switch wired incorrectly. I swapped out the wires and it all looks good now. I tested all parts and everything appears to be grounded and following the correct path. I appreciate all your help. My work days are very long and I have very little time to trouble shoot at night and your suggestions helped me track it down.

So here's the plan for next test.

• Add ground screw to keg.
• Find a source for 20A slow blow fuses.
• Reinstall the Neutral portion of the 240/120 circuit.

Soon I will order a DIN rail and get my 120 hot powered by this cleaner setup. I will also look at the outlet and see if i can get ground off the 30A circuit.

 

[MrH]

Sorry, can't resist another suggestion, as it worked really well for me. Since you have a receptacle for your element, it's a good idea to rig up a light bulb to connect for testing. That way you're not pulling high current and you can work out wiring problems without, er, spectacular failures.


MrH

Edit: Yes, you can find 240V bulbs, but if not, a multimeter will do as well.