Fused distribution blocks - Comparison

[totalconfusion]

Comparison of "100A" fused distribution blocks: eBay VS Blue Sea

Sorry for all the pictures, I down scaled them but maybe not enough


eBay




BlueSea


First off I love that these blocks have an integrated negative block, really clean and easy. I couldn't go back to individual blocks for positive and negative.

I don't know why they both chose to use 10-32 Studs (M5) It just seems really small. I think M6 or M8 would have been a better choice and make finding fittings easier for larger gauge wire.



The conductor near the base of the studs on the eBay job are recessed in, making for what looks like a really shit/no touch connection.




Blue Sea in comparison has a big flat surface to mount to

After deciding to toss the eBay block and find a better alternative is when I came across the Blue Sea product. It seems like it's the only real alternative out there. Is anyone using a different brand? They can't be the only company making blocks like this.

 

[totalconfusion]

And while I'm here ranting about bad conductor contact areas, what do you guys think about this ring terminal? It'll have 16mm2 welding cable going in to it to handle 50A. Doesn't look like a lot of meat on it...



What do you think? Am I just being dramatic?


A couple of alternatives I was looking at:

https://au.element14.com/molex/19193-0219/terminal-ring-tongue-5-16-6awg/dp/1771678?st=ring%20terminal

https://au.element14.com/molex/19193-0251/terminal-ring-tongue-5-16-6awg/dp/3222273?st=ring%20terminal

Nothing I've found seems to have a flared end to make the thin stranded welding wire go in any easier either

 

[svsagres]

Some things aren't worth saving a buck on. My main DC Distribution block on my boat is a BlueSea SafetyHub 150. 4 high capacity for my port/starboard distribution panels (and the DC->DC charger for my starter battery) then a series of six ATO fuses for all the bits and bobs in my electrical closet.

 

[Shimmy]

@totalconfusion can you actually measure the effective contact area? As long as it is more than 16mm2 then no foul. Sadly that is where the smaller studs can be an advantage.

IIRC, you can go down to about 80% of the contact area before it starts to be a real problem at full load.

 

[totalconfusion]

Let's call it 12mm x 12mm x 1.6mm thickness (square)
Minus the 10mm diameter hole (cylinder)

230.4mm3 - 125.66mm3 = 104.74mm3 (54.5% of 230.4)

Or should I be going for surface area and not volume?

 

[Shimmy]

Surface area is going to matter most. If the whole thing is in contact with the terminal then you have almost 4x the surface area in contact. Looking another way, about half that contact area has a cross sectional area of 12x1.6mm, which is still greater than your conductor area (19.2mm2 vs 16). The net effect (if the whole terminal is in contact) is likely equivalent to 2.5-3x the contact area.

 

[totalconfusion]

Surface area is going to matter most. If the whole thing is in contact with the terminal then you have almost 4x the surface area in contact. Looking another way, about half that contact area has a cross sectional area of 12x1.6mm, which is still greater than your conductor area (19.2mm2 vs 16). The net effect (if the whole terminal is in contact) is likely equivalent to 2.5-3x the contact area.

What's the calculation for surface area?

When you say it'll have 2.5-3x the contact area I assume this is because of anything on TOP of the ring terminal biting down on it (washer, nut etc.) and it being attached to the stud. Is that right?

Thanks a bunch Shimmy, I'm going down another vaguely related rabbit hole of fabricating copper bus bars.
What grade of copper, whether or not they should be tinned and if so what type of tinning process.
I'm a bit worried about oxidisation and getting a bad connection, also buying pre-tinned copper bar in Australia is proving curiously difficult.

Anyways thanks for all your help

 

[Shimmy]

What's the calculation for surface area?

When you say it'll have 2.5-3x the contact area I assume this is because of anything on TOP of the ring terminal biting down on it (washer, nut etc.) and it being attached to the stud. Is that right?

Thanks a bunch Shimmy, I'm going down another vaguely related rabbit hole of fabricating copper bus bars.
What grade of copper, whether or not they should be tinned and if so what type of tinning process.
I'm a bit worried about oxidisation and getting a bad connection, also buying pre-tinned copper bar in Australia is proving curiously difficult.

Anyways thanks for all your help

The contact surface area is going to check both the terminal and the lug. The stud doesn't conduct any electricity (ideally); it should just be the contact between the two surfaces.

There are some good electricians on the forum with experience in tinning etc. Theoretically, once you make the connection properly oxidation is no longer a concern... you just need to make the connection right.

 

[totalconfusion]

The contact surface area is going to check both the terminal and the lug. The stud doesn't conduct any electricity (ideally); it should just be the contact between the two surfaces.

Interesting. So does the surface area on top of the lug do nothing then? Even when it's sandwiched with a nut on top, it's not conducting through the stud at all? I wouldn't have guessed that.

Do you remember the process for making connections with copper bar? I guess it'd involve sanding back any oxidised copper and immediately making the connection.

Thanks

 

[JRH]

And while I'm here ranting about bad conductor contact areas, what do you guys think about this ring terminal? It'll have 16mm2 welding cable going in to it to handle 50A. Doesn't look like a lot of meat on it...

View attachment 157093

What do you think? Am I just being dramatic?


A couple of alternatives I was looking at:

https://au.element14.com/molex/19193-0219/terminal-ring-tongue-5-16-6awg/dp/1771678?st=ring%20terminal

https://au.element14.com/molex/19193-0251/terminal-ring-tongue-5-16-6awg/dp/3222273?st=ring%20terminal

Nothing I've found seems to have a flared end to make the thin stranded welding wire go in any easier either

It’s called a cheap Chinese knock off.. there’s everywhere…stick with blue seas in this case or original manufactures on everything if it important…Hell, I expect anyday to see a cheap knock off of a Falcon 9 rocket on eBay…
” BUY IT NOW , only 3 left, SALE , $ 499.00”

 

[Shimmy]

Interesting. So does the surface area on top of the lug do nothing then? Even when it's sandwiched with a nut on top, it's not conducting through the stud at all? I wouldn't have guessed that.

Do you remember the process for making connections with copper bar? I guess it'd involve sanding back any oxidised copper and immediately making the connection.

Thanks

I would defer to an electrician on the proper procedure. Essentially you need to create a smooth, oxidation-free surface, potentially treat it with something that addresses oxidation, and make up the connection. @timselectric can you help here-- what are current recommendations?

Stainless steel is a terrible conductor of electricity, so bolts and washers limit what you will get through the top of the lug.

 

[totalconfusion]

That kind of information would be very helpful. My guess is bright tinned at least 25uM layer C110 or C11000 copper will be the way to go. Thanks in advance tim

 

[timselectric]

Smooth clean connection is the best connection.
The two matting surfaces are for the connection. The hardware (bolts, studs,and nuts) are just for holding the surfaces together. Aluminum and copper can oxidize, depending on the environment. Which is why tin plated is a better option.

 

[totalconfusion]

Smooth clean connection is the best connection.
The two matting surfaces are for the connection. The hardware (bolts, studs,and nuts) are just for holding the surfaces together. Aluminum and copper can oxidize, depending on the environment. Which is why tin plated is a better option.

So if using raw copper bar, give it a rough sand to remove the oxidised layer if any, then give it a fine polish, thus smoother. But if using a tin plated copper bar, would you recommend just leaving it and not sanding the surface as it'll be smooth enough and probably not be oxidised and sanding it would only remove the tin layer?

Are there any oils or treatments you'd give to the raw copper after sanding/polishing, or should a tight connection fuse the surfaces adequately for prolonged use?

Thanks for your input

PS: Is there really much difference between C110 and C11000 copper grades? Are these the most common copper bar types around used for conducting?

 

[timselectric]

So if using raw copper bar, give it a rough sand to remove the oxidised layer if any, then give it a fine polish, thus smoother. But if using a tin plated copper bar, would you recommend just leaving it and not sanding the surface as it'll be smooth enough and probably not be oxidised and sanding it would only remove the tin layer?

Correct

Are there any oils or treatments you'd give to the raw copper after sanding/polishing, or should a tight connection fuse the surfaces adequately for prolonged use?

depends on the environment. Humidity is a problem.
There are many products that help prevent oxidation.
Just choose one that doesn't decrease conductivity.

PS: Is there really much difference between C110 and C11000 copper grades? Are these the most common copper bar types around used for conducting?

The more pure the copper is, the better.
Which is why all copper conductors are 99% pure.

 

[totalconfusion]

depends on the environment. Humidity is a problem.
There are many products that help prevent oxidation.
Just choose one that doesn't decrease conductivity.

I'll give getting tinned copper bar another go but it's proving strangely difficult in Australia.
Any brand or chemical names of raw copper treatment product off the top of your head?

Thanks for the help mate

 

[timselectric]

No lox
De ox
Deoxit

 

[timselectric]

Another option is to tin your own bar.

 

[totalconfusion]

Another option is to tin your own bar.

Yeah I thought about it... But geez I'll probably end up spilling acid everywhere and doing a terrible job.
There's got to be someone selling tinned copper bar around here.

 

[curiouscarbon]

Yeah I thought about it... But geez I'll probably end up spilling acid everywhere and doing a terrible job.
There's got to be someone selling tinned copper bar around here.

hello! diy tinning is also too much of hassle for me right now. found these on amazon, tinned copper. have handled it and they seem pretty decent quality. not sure if any of the available dimensions would work for you; https://www.amazon.com/gp/aw/d/B09TFLWZ55

good luck with your projects!