Lug holes too big

[Dicey2024]

I have 1/0 -3/8 lugs my dc fuse post is 1/4 can I use washers to increase connection?

 

[sunshine_eggo]

No. Get smaller ring terminals. By sandwiching with washers, you increase the resistance with the washer between the terminals.

 

[Pierre]

Better to source lugs with smaller size holes.

 

[timselectric]

If that washer is tin coated copper, yes.
If not, it will make for a bad day.

 

[silverstone]

Using washers is NOT an issue if they are NOT in the main current path (e.g. when torquing the cable lug from above with a nut / bolt), and where the tinned copper cable lug is in direct contact with copper posts / tin-or-nickel plated aluminum posts. Make sure to clean the posts especially if they are pure aluminum !!!

If the washer is in the current path like you illustrate (I am referring to the BOTTOM washer), then IT IS an issue. The bottom washer, if steel, will get red hot. The top washer and nut is not the issue. THE ISSUE IS THE BOTTOM WASHER.

If the washer is in the main current path, galvanized steel / carbon steel has approx. 10 times more resistance than copper ... It will glow red and melt your plastic. If stainless steel it's maybe 4-5 times even more worse (40-50 times worse than copper) ...

Your plastic will melt and most likely start a fire ...

You could in theory cut a small piece of copper bar (e.g. square) and drill a hole in it to put as an interface material between the posts and your cable lug. But it's probably going to be more work, complicated, less good of an electrical connection, compared as to getting the proper cable lug in the first place.

 

[pollenface]

make your own out of crushed copper pipe

 

[crossy]

As above, the correct size lugs should be readily available.

For high-current connections there really is no viable alternative.

EDIT one of many, many. https://www.amazon.com/Ga-Stud-Copper-Lugs-Pack/dp/B00O7S7PM2

 

[chrisski]

If that is a Blue Sea ST blade fuse block, it is a not 1/4” stud. Specs make it look like a #10.

ST Blade Fuse Block - 12 Circuits with Negative Bus and Cover - Blue Sea Systems

Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.

www.bluesea.com

The block is rated for 100 amps total, 60 amps per circuit.

I fused mine for 50 amps and used 8 AWG 75 c wire with this stud

https://www.amazon.com/gp/aw/d/B073Y8PBMN?psc=1&ref=ppx_pop_mob_b_asin_title

 

[Steve_S]

Better to use the "Best Fit". Selterm makes some of the best HD Tinned lugs out there.
These can be had off Amazon/Ebay as well... Selterm has stores in both.

Marine Grade Tinned Copper Battery Cable Lugs | SELTERM

SELTERM Tinned Copper Battery Cable lugs are ideal for making marine grade cables that can withstand advese conditions. UL & CUL listed, rated to 600V DC and salt spray tested, they are ideal for boats, pleasure crafts, heavy duty truck, snowmobiles etc.

selterm.com

 

[Dicey2024]

Thank you I have the smaller lug holes 1/4
I looked for 1/0 #10 lugs and couldn’t find any.

Also can I attach the fuses like this

 

[silverstone]

Thank you I have the smaller lug holes 1/4
I looked for 1/0 #10 lugs and couldn’t find any.

Also can I attach the fuses like this View attachment 190429

The hole of the fuse terminal seems also quite big compared to the stud though.

There seems a lot of surface inside the hole of the busbar/fuse that you just installed that is NOT used around (or under) the stud.

This means that the electrical connection will maybe only use 10% of the rated cross-section or so. Thus similar problem as the washer IMHO.

 

[Steve_S]

1AWG, #10 Stud, Tinned Copper Battery Cable Ends, Wire Lugs, Marine Grade, MD0110P​

1AWG, #10 Stud, Tinned Copper Battery Cable Ends, Wire Lugs

SELTERM Marine Grade Wire Lugs are made from 99.9% pure annealed tinned copper, providing a high degree of conductivity for maximum current flow. This particular variant is generally suitable for use with 1 Gauge Battery Cable & # 10 (M5) Stud.

selterm.com

No fuse can take stresses, most especially T-Class which can separate. Fuses do require proper holders.

 

[Checkthisout]

Thank you I have the smaller lug holes 1/4
I looked for 1/0 #10 lugs and couldn’t find any.

Also can I attach the fuses like this View attachment 190429

No. Put the fuse in a holder.

And no, that big fuse needs to be where the conductor connects (or as close as possible) to the battery.

 

[Checkthisout]

Also, in your original photo, when the terminal hole is too big you're losing contact area.

It's just catching the edges of the terminal.

That cable is also unnecessarily large for feeding that fuse panel.

 

[Checkthisout]

make your own out of crushed copper pipe

No, don't do this.

 

[Dicey2024]

No. Put the fuse in a holder.

And no, that big fuse needs to be where the conductor connects (or as close as possible) to the battery.

I have multiple fuses. I have a fuse on the battery, this one is for the fuse box - the fuse box says to use a fuse less than 125amp

 

[Dicey2024]

Also, in your original photo, when the terminal hole is too big you're losing contact area.

It's just catching the edges of the terminal.

That cable is also unnecessarily large for feeding that fuse panel.

The fuse box is rated for 100amps and it said to use 1/0 cable

 

[Dicey2024]

If that is a Blue Sea ST blade fuse block, it is a not 1/4” stud. Specs make it look like a #10.

ST Blade Fuse Block - 12 Circuits with Negative Bus and Cover - Blue Sea Systems

Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.

www.bluesea.com

The block is rated for 100 amps total, 60 amps per circuit.

I fused mine for 50 amps and used 8 AWG 75 c wire with this stud

https://www.amazon.com/gp/aw/d/B073Y8PBMN?psc=1&ref=ppx_pop_mob_b_asin_title

Thank you I used your link to find #10 lugs for 6awg

 

[Checkthisout]

The fuse box is rated for 100amps and it said to use 1/0 cable

That fuse box will not do 100 amps. Trust me on that.

Just calculate your actual loads and use wire big enough to carry those amps.

It will be a much easier install with smaller wire.

It also needs to come straight out of the bottom or you won't be able to get the clear lexan cover on.

 

[HighTechLab]

1/0 AWG 1/4" ring terminal lugs:

Tinned Copper Battery Cable Lugs - 10 Pack | Current Connected

Experience superior conductivity and durability with our Tinned Copper Battery Cable Lugs. Customizable options for a secure connection.

www.currentconnected.com