Burn up Bus Bar

Can someone tell me why my negative wire from my 12v 8gpm pump melted my bus bar? Is the 14 awg wire to small? I just built this thing and ran the pump for 5 mins when it started to melt.

Not sure, so wait on the others to respond. It looks like the busbar itself melted down, not the wires. That would seem to me to indicate that the wires were ok and it was the fuse box itself that was not up to the task or was defective.

Did you check the specs on the fuse box and the pump?

No way for me to know, but you may just have a defective fuse box.

It got hot. A bad connection increases resistance. Increased resistance increases heat. 14 awg needs a 15 amp fuse on the hot side. 12 awg, 20 amp, ect… @Nickski is gonna be the guy to hear from on this one.

I had a 20 amp fuse on it. Just what i had laying around. Same as the bus bar. So if i use a small fuse wouldn’t it pop before melting? Indicating i have anothet issue? I hate wiring.

I’ll bet you had a bad connection at the melted plastic but yes, the wire size determines the fuse / breaker size so it will blow / trip before the wire is introduced to more amperage than it can carry. A bad connection would equate to having a 14 awg wire but a 30+ awg connection, if that makes sense. Ohm’s law doesn’t care what anybody thinks. When it comes to wire connections, I’m a big fan of flux, solder & heat shrink but electricity is not my forte. Stay tuned for good answers.

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I just remembered that I have another fuse that came with the pump right off the pump. I forgot to check what size but that didn’t blow. So maybe it is the wrong bus bar.

You say the negative wire, but your pic shows a burned connection in what should be the positive side. What’s the max power rating of your pump?

You need to start with the max rating of your pump and design around that. Wire size, fuse panel, and fuse size are dictated by the pump. But, if wired up right, your fuse should blow well before you melt your connection like that

Sorry for the multiple post, but looking again, I don’t think you’re using that fuse panel right. I don’t see anything connecting to the main terminals for incoming power and ground. Got another pic from straight on?

I mispoke. It’s my positive that burned up. The bottom center screw goes to positive on battery and the top center screw goes to my ground on my trailer. You can kinda see them. I can get a better pic tomorrow.
Max amps for my Everflow pump is 23 and the bar says its max is 30 amps.
This is the bus bar.

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Can you explain your setup a bit more? You have just two hot wires coming off the panel, but 4 grounds.

The pump comes with 12 awg. I used 14 to connect to the pump wires to my switch and to my bus bar. From bus bar the wires go back to another different type of bus bar powered by my battery. The pump to the right is the one with the issue. My other pump is a 5.5 and it has 14 wire coming off the pump.

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Just like a nozzle chart in PW, elec wire has a wire chart for feet and amperage.



I’m only running it about 14 inches so 14 would be ok. I’m gonna go to 12 anyway.

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Still, IF the wire was the problem, then the wire would melt down.

Have you tried a new fuse panel? That looks like it’s burned from a poor connection, especially since the fuse didn’t blow. I wonder if was an issue internally between the one side of you fuse and the terminal. A broken or poor connection from manufacturing. You can see the burned area is not just the terminal, but the one side of the fuse too.

I changed the wire to 10awg and a larger ring connector. I put the ring connector on the positive post because the connector wouldn’t fit in the tiny spot similar to the one that melted. Ran it for 10 mins and it didn’t even get warm. Last time it melted in under 5 minutes. Thank you all for the help.

Just out of curiosity, the wire you used were copper both times correct? Just asking because that aluminum wire and the tinned copper carry heat differently.

I’m no electrician, but I have been doing a lot of reading and research lately because I’m contemplating going with solar. A motivating force for this change is the fact that they just raised rates 15% in January and they are contemplating another raise.

When it comes to things like ring terminals and battery posts I’m a big fan of dielectric grease to help prevent the connections from corroding. Corrosion leads to bad connections.


They are noth stranded copper.