Hi all. I'm using the Blue Sea systems PowerBar 1000A bus bars which are made from tinned copper. If I want to ensure a very good and effective connection to the bus bar, does it make a difference if I use copper or tinned copper lugs? And if I should use tinned copper lugs, does that then mean I need to use tinned copper cable as well for those tinned copper lugs? Or am I over analyzing this? Thanks.
Copper or Tinned Coppers Lugs for Tinned Copper Bus Bar
- Thread starter Henderson
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Tinned copper for the lugs. For the wire it doesnt matter. Primary reason for tinned vs bare copper is to reduce the chance of oxidation.
Copper, when exposed to the elements, will oxidize (turn green, hence the green rooftops).
In a wire its protected by the insulation. On a busbar it's exposed to humidiy, thus might create oxidation.
Copper, when exposed to the elements, will oxidize (turn green, hence the green rooftops).
In a wire its protected by the insulation. On a busbar it's exposed to humidiy, thus might create oxidation.
Ok thanks. Makes perfect sense.
One little related note; some may say tinned lugs without peepholes are better at protecting the cable than those with peepholes. Purpose of the peephole however is to allow someone inspecting the cable to verify it is fully seated in the lug.
Edit: assuming not using tinned copper cable since it should have no issues with either.
Edit: assuming not using tinned copper cable since it should have no issues with either.
You can check the manual/specs for a lug.. this one from Thomas & Betts:
You don't solder lugs...crimp only.
John Frum
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I think you are all assuming compression lugs.
I've seen videos where the ocean going installations use...
marine grade tinned copper wire.
tinned copper compression lugs with inspection port.
finished with marine grade heat shrink with adhesive over the inspection port.
Myself I just use mechanical lugs, but my stationary install is temperature and humidity regulated.
I'm also pushing <66 amps through 2 awg xhhw-2 wire.
I will let you all know if/when I regret my decision.
@Henderson how much current do you plan to move through the Powerbar 1000?
Is your application mobile or stationary?
Is salt air going to be an issue?
I've seen videos where the ocean going installations use...
marine grade tinned copper wire.
tinned copper compression lugs with inspection port.
finished with marine grade heat shrink with adhesive over the inspection port.
Myself I just use mechanical lugs, but my stationary install is temperature and humidity regulated.
I'm also pushing <66 amps through 2 awg xhhw-2 wire.
I will let you all know if/when I regret my decision.
@Henderson how much current do you plan to move through the Powerbar 1000?
Is your application mobile or stationary?
Is salt air going to be an issue?
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Hi John, my system will be stationary. We do get some salt spray in the air- I'm about 1.5 to 2 miles from the coast so over time you do tend to notice the wear and tear from the salt. In terms of amperage through the bus bar, no more than 500 to 550 amps at the very maximum but consistently I would probably estimate between 200 to 300amps.
Risky Rob
Solar Enthusiast
I set the cable in the lug with a punch and hammer, crimp with a vise, then solder. Flux inside the lug seems to draw the solder in.
If your humidity isn't low or the environment isn't clean (salt qualifies as not clean) then tinned is the way to go. I'm using bare copper bus bars to connect some of my components. I use anti-oxidation paste on the connecting surfaces. So far, it looks fine. However, my humidity is very low, like 20% or less.
You can do what you want but they are designed to be crimped.
Risky Rob
Solar Enthusiast
I make my own lugs. You seem to think there's only one way to do things.
LOL...let me guess...with copper pipe!
John Frum
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550 amps is a metric shit ton of amps.
That requires 500 mcm cable and a 700 amp fuse if its going through 1 wire.
What is your system voltage?
Can you go up in voltage to decrease the amperage?
48v. That 550 is really set as a maximum bearing capacity in the unlikely event that I have everything running at the same time, so for eg, ac running, EV charging and electric oven all going at the same time which is unlikely, but being the electrically paranoid person that I am, I want to be able to have the capacity to handle it if it happens.
Risky Rob
Solar Enthusiast
So copper is bad? Do your brass lugs come from China?
I'm glad you mentioned about cable sizing. I'm looking into utilizing parallel AWG cables at varying parts of the system to handle the load.
John Frum
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I'm guessing you have 4 inverters and 6 batteries, confirm?
The biggest powerbar has 12 studs.
You can't really double up any cables and I don't see any reason why you should.
I would be glad to suggest a topology if you tell me what all your loads, sources and batteries are.
By the way, this is how I came up with the 500A max use case. I will be using 4x EG6500EX inverters which provides a max of 26KW. I anticipate that my max draw will never be over 20KW across those 4 inverters. I'm assuming I am going to lose efficiency from all the cable runs and the inverter losses as well and I am estimating a total loss of 15%. Which means, if I want the 4 inverters to produce 20kw, I need to have 20kw/0.85 coming originating from the battery bank which is 23.5kw. Divide that by 48 and I arrive at 489 amps, round up to 500A.
John Frum
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Its my policy to always design for the full capacity of the inverter(s).
They are copper lugs...you don't use brass..and yes, they are from the US.
Even worse that I have seen are people using flattened copper pipe for bus bars.
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96 batteries in total hopefully. Looking at the 310AH cells. The system won't start out with 500A but I'm trying to design it such that it can handle that capacity at the end state. The thinking is 3x 2p16s configuration. In terms of loads...3 inverter ac units (2 will typically pull 1.2KW each and the other one will pull 2Kw...this is when they're running and not startup). Lights, fridge and deep freeze, internet, ceiling fans...what I call more passive background loads, all of these are at approx 0.8 to 1.3kw. When the EV is charging, that's 7.2KW. Electric oven around 4kw. Other misc items such as treadmill (0.7kW), microwave (0.9KW). A number of desktops in the house when all are on will take approx 1kw. It's extremely unlikely that all of these items will be on at the same time.
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