Insulating A Bus Bar

[Grace and Favour]

May I draw upon the wisdom of CWDF's electrical wizards, please?

 

Come the day when we replace our battery banks, (with some Trojan 105's rather than the Numax we have currently) I shall follow one of Chris Gibson's wiring plans - with equal length tails going to bus bars. The configuration will be 12v.

 

I shall also use the bars to receive the cables from the solar controller (fused at 400A)

 

I've sourced some good, chunky copper bar, and will kit them with stainless steel studs for the cables. Does anyone know what level of insulation I require/(or where I may research it) - and what material may be best for the job, - please?

 

Many thanks

 

Dave

 

 

[Charlotte Burnett]

Or just buy Blue Sea bus bars with clip on covers.

[nicknorman]

I'm inclined to agree with Charlotte - that is by far the easiest and best way! However if you want to mount the bus bars on something, dry wood would be adequate. It will have a very tiny leakage current but that will be insignificant at 12v. But at least for the +ve bus bar, it will need to be covered to prevent accidental shorting and once again a proprietory covered bus bar is the best way to go.

[Grace and Favour]

Ah yes, purchasing a couple was my first thought

 

 

But they tend to be rather expensive (I think) (Blue Sea bus bar)

[FadeToScarlet]

I put them in 240v plastic surface mount two gang plug boxes, with a cover over. Spaces easily pushed out for the 70mm^2 cables to enter, and an easily unscrewed and removed blank cover plate for access.

[Ex- Member]

I've used Heat Shrink in the past, the glued stuff is brilliant.

 

All out battery connections go to single posts made from 10mm Brass studding & Brass nuts set into hardwood. They are then put inside ABS boxes. Really easy to make using off cut hardwood, You can make really nice ones using hardwood hole cutout waste sanded down and threaded, brass studding is pricey though but a lot cheaper than buying bus bars & posts.

 

[Charlotte Burnett]

WTF install do you have that you need 600A bus bars? Normally something like this is more than adequate

 

http://compare.ebay.co.uk/like/221239685976?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&_lwgsi=y&cbt=y&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=63&ff19=0

 

What output of solar do you have and with what controller? The biggest ones I know of are 80A Outback's. If you really do need to be fused that high then I would suggest you also need to run straight back to the batteries on the shortest possible length of 150mm2 or bigger cable. How many batteries are you charging? Is propulsion electric? I want to see this!

[GUMPY]

Personally I wouldn't use those bus bars for connecting batteries there are only two usable terminals.

I use these

http://pages.ebay.com/link/?nav=item.view&id=230400356291

Enclosed in abs boxes.

[by'eck]

I'm inclined to agree with Charlotte - that is by far the easiest and best way! However if you want to mount the bus bars on something, dry wood would be adequate. It will have a very tiny leakage current but that will be insignificant at 12v. But at least for the +ve bus bar, it will need to be covered to prevent accidental shorting and once again a proprietory covered bus bar is the best way to go.

 

Although marine ply was used on my last boat to support high current battery studs well away from any damp, I would recommend something like thick nylon/plastic strip for a narrowboat plus a cover of course for postive bus.

 

I do however agree that a propriety busbar is the best. I used these although I admit not cheap - there are 500 amp versions as well.

Edited August 5, 2013 by by'eck

[luctor et emergo]

Am I the only one who read the topic title, and wondered why one would want to insult a bus bar?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yeah, thought so..

[nicknorman]

Insulting a bus - definitely, they pull out just as you approach, lumber along at 20mph chucking out black smoke, stop at bus stops without bothering to pull into the side of the road, have squealing brakes etc etc and all whilst only carrying one person - an OAP who likes to spend their day travelling round and round on their free bus pass. What's not to insult?

 

Bars on the other hand, are surely a good thing?

[dmr]

I am not at all convinced that bus bars are really necessary unless you want the personal satisfaction of creating the ultimate electrical system (and there is really nothing wrong with getting satisfaction from engineering projects!).

 

A conventional arrangement with linking cables should be fine as long as you follow the basic rules such as taking positive and negative feeds from opposite ends of the bank. This is particularly true for Trojans where you will probably only have two "batteries" (each battery having two Trojans in series).

 

I have checked the current balance on my installation (which has 35mm2 cables) using a good clamp on probe and it was spot on.

 

.............Dave

[blackrose]

Ok, I'm going to admit my electrical ignorance here by asking what the difference is between using an expensive busbar, or just connecting all the 8mm ring terminals together on a 25mm x 8mm dia stainless nut & bolt with a stainless washer at each end and perhaps a couple of stainless spring washers? Of course, with the nut & bolt you can't disconnect any single terminal without dismantling the whole lot, but so what? How often do you disconnect these connections around batteries anyway?

 

Do busbars have any other advantages?

Edited August 5, 2013 by blackrose

[nicknorman]

Ok, I'm going to admit my electrical ignorance here by asking what the difference is between using an expensive busbar, or just connecting all the 8mm ring terminals together on a 25mm x 8mm dia stainless nut & bolt with a stainless washer at each end and perhaps a couple of stainless spring washers? Of course, with the nut & bolt you can't disconnect any single terminal without dismantling the whole lot, but so what? How often do you disconnect these connections around batteries anyway?

 

Do busbars have any other advantages?

Advantages: mainly because if you try to connect multiple ring terminals to one bolt, after the first few the crimped bit gets in the way and it won't all lie flat and at the very least you have to have the cables exiting in all directions,probably not the direction you want - definitely an issue with large section cable.

 

You also may get lower resistance connectors since the current doesn't have to flow through all the intermediate ring terminals to get to the middle one (bearing in mind the connection to the threaded part of the bolt is not good).

 

Looks neater? Well not an issue if you are not fastidious, until someone comes along and tries to work out what goes where.

Edited August 5, 2013 by nicknorman

[RLWP]

I'm inclined to agree with Charlotte - that is by far the easiest and best way! However if you want to mount the bus bars on something, dry wood would be adequate.

 

Slate is so much more attractive though

 

 

Richard

[David Mack]

 

 

I'd like to see that in a trad engine 'ole!

[RLWP]

So would I!

 

I bought some cheap bakelite meters, a couple of large wooden boxes and some ancient switched fuseboxes ages ago with the intention of doing that. The right boat hasn't turned up yet

 

Richard

[Grace and Favour]

Thanks for the input, everyone . . . it has helped .

 

I have seen Julynian's pics of his new battery set-up before - but the reminder was most useful, and I find myself drawn to making a similar cabinet to Richard's slate mount (though I think I'd need to frame it in Japanese Walnut picked out in Ebony - if I'm going OTT - then I'll go the whole hog!).

Thanks also for the links to various bus-bars - and, Charlotte, the reason why I employed a 400A fuse on my Outback, was because that's what the wiring plan specified.... and the reasons why I am after heavy bus bars is that I like nice, tight electrical connections, particularly on batteries, and with studs that will handle the 'squeeze'.

 

(and, moreover, I take pride in doing a tidy job)

 

Thanks everyone

 

Dave

[blackrose]

Advantages: mainly because if you try to connect multiple ring terminals to one bolt, after the first few the crimped bit gets in the way and it won't all lie flat and at the very least you have to have the cables exiting in all directions,probably not the direction you want - definitely an issue with large section cable.

 

You also may get lower resistance connectors since the current doesn't have to flow through all the intermediate ring terminals to get to the middle one (bearing in mind the connection to the threaded part of the bolt is not good).

 

Looks neater? Well not an issue if you are not fastidious, until someone comes along and tries to work out what goes where.

 

I can see the advantages of all your points there, but not your premise which I've highlighted in bold. The threadd bolt itself does not really form part of the electrical conection - its function is simply to clamp the terminals together. If threads caused a connection problem then why are your battery posts threaded? Ring terminals that you put over the battery posts don't connect to the threads, they connect to the base of the terminal under pressure from the nut.

 

Edited August 5, 2013 by blackrose

[nicknorman]

I can see the advantages of all your points there, but not your premise which I've highlighted in bold. The threadd bolt itself does not really form part of the electrical conection - its function is simply to clamp the terminals together. If threads caused a connection problem then why are your battery posts threaded? Ring terminals that you put over the battery posts don't connect to the threads, they connect to the base of the terminal under pressure from the nut.

 

Yes absolutely right. My point was that there is not a good connection to the threaded bit since its not under pressure. As you say, the connection is via the faces of the ring terminals. But if a large current has to pass from one ring terminal to another, via several intermediate ring terminals, each connection represents a small but non-zero resistance, and a resistance that can increase if any corrosion develops.

[smileypete]

Tufnol is quite good for bus bar supports, google 'tufnol bus bar'

 

And as Julynian says, ABS project boxes make good covers, some sizes are available in red:

 

http://www.ebay.co.uk/sch/i.html?_nkw=red+abs+box&_sacat=12576

 

cheers, Pete.

~smpt~

[Grace and Favour]

Thank you Pete

[Arthur Brown]

Some of Maplin's boxes may suit, some of their heatshrink sleeve may help too. RS and CPC do more and bigger sizes, including some glue lined heatshrink.

[smileypete]

Also worth tinning the bus bar if not already done.

 

Blowlamp, rosin flux off Ebay, plumbers solder, pure cotton rag for wiping the excess off, practice on some scrap copper maybe. Might have to retap any threaded holes though.

 

cheers, Pete.

~smpt~