question

Rob avatar image
Rob asked

Busbar with thermal circuit breakers

Numerous Victron schematics show thermal circuit breakers connected with a busbar. How is this implemented? The thermal breakers used in marine systems have a raised tab that seems to prevent installation of a busbar.


From Victron schematic:


breakers-with-busbar.jpg

Closeup of breaker:

breaker-detail.jpg

busbar
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4 Answers
klim8skeptic avatar image
klim8skeptic answered ·

The terminal would seem to accommodate multiple hex nuts.

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Rob avatar image Rob commented ·
Are there corrosion resistant hex nuts that are acceptable as conductors? Stainless steel is a poor conductor. Marine safety standards don’t allow stainless hardware to be part of the conducting path.
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airstream-installer avatar image
airstream-installer answered ·

I would just remove the divider if I were going to do it this way. If you are going to “stack nuts” to give you the clearance you need DO NOT use stainless steel nuts. Stainless is a very poor conductor and will cause a heat build up. Best would be to use a copper spacer or brass or bronze nuts.

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sebastian-hoitz avatar image sebastian-hoitz commented ·
I am currently looking at the same issue. I bought two circuit breakers. Another argument against stacking the nuts: There is barely any terminal left to add another nut for bolting onto the bus bar.


So I think the best solution would indeed be to remove just enough of the divider to allow installing the busbar. Note: It would probably also be useful to either: still use a copper washer on the terminal or countersink the top-left mounting hole so that the screw does not touch the bus bar.

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Phil Gavin avatar image
Phil Gavin answered ·

I have used a flavour of this type of breaker. In a nutshell, they are junk.

Erratic, sticky, generally more trouble than they are worth.

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drlbradley avatar image
drlbradley answered ·

Im with Phil, I had a couple of these - they were rubbish, would trip with only half the load applied. Instead I went for properly rated fuses and separate (Blue Sea Marine) switches.

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