Accidental Arc Welder

[sjturbo]

I needed to check lug size on my shunt today to complete some charging cables. I turned off shore power, and turned off batt. disconnect. While wrenching the shunt bolt off and the wrench slipped and shorted the pos side of the inverter 100A fuse (which I had removed the plastic safety cover from)to the ground lug, and created my own arch welder. I bet most of you have a disconnect between the batt. and the inverter? I will very soon!! I thought it had taken out my inverter and Victron monitor. But fortunately the only casuality was my ego, and the 100A fuse! Oh, and a slight divot in the wrench.

[NinerBikes]

msiminoff wrote:
Yes, unfortunately the "wrench-battery-arc-welder-syndrome" is an all too common occurrence. When I was a kid I worked at a hot-rod shop and one of the other mechanics there dropped a wrench which shorted between a pos. battery terminal and the vehicle's frame. The wrench welded itself in place and glowed orange before he was able to grab another tool to knock it off. It scared the heck out him… and me too!

To prevent this I have battery disconnects and have also installed fuses directly to each of my (+) battery terminals.


As an additional (and inexpensive) preventive measure when working on my electrical system, I always wrap the handles of my open end wrenches (and/or screwdrivers) with Rescue Tape.

Glad to hear that the only damage was to your ego 😉
Cheers
-Mark

Putting that on there, now you have 3x the amount of hot contact surfaces on the positive side to bump against ground. I'd put the disconnect on the ground wire, myself, so that the whole frame and all other metal parts are not hot, if by chance you touch the positive against anything grounded.

[Bill_T]

Guys remember to remove any finger rings before working on your electrical systems.
I wish I could find the pic of my buddy's finger when he grounded a wrench while working on his 24 volt jeep. Not a pretty sight.

[Snowman9000]

wa8yxm wrote:
Did something like that to one of my Inverter fuses.. SIXTY BUCKS (ouch).

T-Fuses are expensive.

Not sure which one you are referring to...

Anyway, the one I showed is about $37 for the holder and the fuse. Extra fuses are about $12. Shipping included in both prices.

[wa8yxm]

Did something like that to one of my Inverter fuses.. SIXTY BUCKS (ouch).

T-Fuses are expensive.

[Snowman9000]

I had one of these on my last RV. The batteries were in a real hard place to get to. I think I'm going to put on my current MH too. The hole in the plate is 3/8", and the stud is 5/16, IIRC.

https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

[msiminoff]

Yes, unfortunately the "wrench-battery-arc-welder-syndrome" is an all too common occurrence. When I was a kid I worked at a hot-rod shop and one of the other mechanics there dropped a wrench which shorted between a pos. battery terminal and the vehicle's frame. The wrench welded itself in place and glowed orange before he was able to grab another tool to knock it off. It scared the heck out him… and me too!

To prevent this I have battery disconnects and have also installed fuses directly to each of my (+) battery terminals.


As an additional (and inexpensive) preventive measure when working on my electrical system, I always wrap the handles of my open end wrenches (and/or screwdrivers) with Rescue Tape.

Glad to hear that the only damage was to your ego 😉
Cheers
-Mark

[DaHose]

I have plastic coated tools I grab at when taking off battery terminals and on my coach battery I have a tool-less quick disconnect.

Jose

[Harvard]

CloudDriver wrote:
Learned that same lesson years ago with a car battery. Since then I always disconnect the ground cable from the battery before doing anything else.

x2

[ledcomp]

I use a non-metalic 3/8 ratchet extension. This way it does not matter if the ratchet bumps something. The only live part is the socket. Works great.

[Matt_Colie]

Wow, I bet you are the only one to do something like that.....
At least nothing took serious damage.

Matt

[hypoxia]

I won't use a box wrench on a battery, an open end wrench can be knocked off of the nut easier.

[DaHose]

One of the screw lugs on my chassis batteries was blown clean off by a PO. Musta scared the poop out of somebody. Still works fine, but gives me a chuckle every time I open the hood.

Jose

[westend]

Yeah, plasma!!

I used to tape a wrench when I worked on batteries with similar terminals. Now, I just try to be conscious of where the metal is swinging.

You know, this might be just the start of a process. I worked my way up to cross connecting 460V welding stations. :B Unfortunately very little sparking but it is interesting to see that 300 lb machine dance on the floor.

[CloudDriver]

Learned that same lesson years ago with a car battery. Since then I always disconnect the ground cable from the battery before doing anything else.