Making a switch panel - Busbars...

C

chrisbitz

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Bromley, Kent - Sail in Medway
www.freyacat.co.uk
I'd like to make a new switch panel - the existing one has 6 switches, but I want a few more, to separate some circuits...

I see busbars mentioned, and I've got one now, but it's not insulated, and I would have thought that for safety, why aren't busbars insulated... and why don't people use positive and negative busbars in a switch panel?
 
chrisbitz said:
I'd like to make a new switch panel - the existing one has 6 switches, but I want a few more, to separate some circuits...

I see busbars mentioned, and I've got one now, but it's not insulated, and I would have thought that for safety, why aren't busbars insulated... and why don't people use positive and negative busbars in a switch panel?
Click to expand...


Not sure what you are looking at but insulated terminal blocks with jumpers might be better eg http://www.power-store.com/view-item.asp?itemid=614&id=100&


614_2076.jpg

Available in various lengths

But you can get insulating covers for ordinary bus bars

I have to confess that the two busbars in my switch panel are in fact ordinary choc-box type connector strips. I may have found a couple with brass grubscrews or I may have changed the screws ....... or I may not have. They've been in service for about 30 years and I am confident that they will see me out what ever they are.
 
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A true bus bar is held very rigidly so it can not move hence no need to insulate it. It is always mounted behind panels.
I remember as a junior trainee we were taught that when working in telephone exchanges never wear a metal wrist watch band. The bus bars there are typically 35mm by 6 mm brass strip often many metres long. +ve and -ve were separated by about 50 mm. Often just the right distancee for a hand to pass through. A metal watch band could then short the bus bars and melt.
For your boat as said looped chocolate block connection is OK Or you cna get actaul brass bars with bolt connections for wires for both +ve and -ve. good luck olewill
 
Why not drop into your local electrical trade store and purchase a properly insulated and weatherproof power distributuion box of the 250 volt ac or whatever your power at home is and convert (wire) it a 12 volt DC unit.

Cheap, meets the standards, won't rot or fall apart. will take fuses or circuit breakers.

I have wired many of them over the years and never had a problem.

Good luck and fair winds. :)
 
I rewired my boat recently to rationalise things.
I made a negative busbar by cutting a strip of 20x 3 flat stainless and welding a number of studs to it. Actually i drilled holes and cut the heads off some 6 mm stainless bolts.

Stainless steel is not actually a very good conductor, but over tiny distance and large x section i dont think its a problem.
I also made a positive busbar to accept the battery feed and the motor charging feed and future solar feed.
The 6 mm studs could equally be done with a machine screw and a retaining nut if you dont have stainless welding capability.

I have 6 switch-plus-fuse circuits and it quickly became apparent that some of these would have multiple circuits attached. I split my cabin lights between two circuits so that a fuse blow wont leave me in total darkness. Soldering 4 or 5 things to the one tag seemed a bit primitive so i bought a 10 mm thick UltraHighMolecularweightPolyethylene cutting board at the kitchen shop and cut a strip some 180 mm long x 20 mm wide and drilled and countersunk 6 holes through it. In each hole i inserted a 4 mm (3/16 maybe)brass machine screw with lots of excess length. I mounted the block in the switchboard with the studs sticking upright. I bought lots of nuts. For each switch/fuse circuit i first ran a wire to a stud on this block as a supply . Then as i added each circuit i crimped or soldered* a ring on the positive and negative wires and simply added them to the appropriate studs separated by nuts.
I was well pleased with the result and adding or changing stuff in future will be really easy.


*to avoid thread drift, I am not saying whether i solder or crimped or both. Nor will i mention anchors.

Good luck
 
nigelmercier said:
The 12V "bus-bar" I installed on the wooden door of my switch panel locker is an M8 stud epoxied into the wood. Connections are made with ring terminals. Cheap, neat, and secure.
Click to expand...

The only caution to add is that I've often been advised that no more than four connections should be made on each post. I guess this is based on practical experience as the security of the group lessens as each extra is added and thus the contact may reduce, increasing resistance. I may be wrong as to the reason, but I've stuck by the practice and had no problems.

Rob.
 
I fitted Busbars last season when I did a refit.

After a particularly bouncy journey my boat electrics went dead. I pulled everything out, checked connections and everything was fine. I then started to unscrew the Busbar screws to take off my connections just in case I had dodgy end connectors. In typical fashion I unscrewed the wrong way first where I discovered the Busbar screws holding down the connectors was slightly loose. As soon as I tightened them all the electrics sprang to life. The boat vibration loosened the screws on the Busbar!!!

So this winter I'm applying some of that lock thread glue to each of the Busbar screws so it doesn't happen again.

When I discovered this it was a proper "no way" moment so whatever you install think of this scenario. it's at the extreme end of the "this could happen" scale but it happened to me.
 
chrisbitz said:
that looks lovely, but starting at £96 for 4, they're a bit too pricey for me.

http://www.ebay.co.uk/itm/DC12V-8-G...ther_Computing_Networking&hash=item232c1b4351

this is more like what I'm looking at now...
Click to expand...


Be careful with panels. I've bought before off the interwebs and the quality of the wiring/soldering can be carp. Buy in a chandler so you can inspect before you part with your hard earned. Again, this is from experience.

I bought my Busbars from The Wiring Project also known as IEM services. I found this chap to be a reliable service and had much of what I needed for my refit. I think you'll find this chap is much cheaper.
 
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