Busbar with thermal circuit breakers

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Rob asked Mar 8, '22

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:

Closeup of breaker:

busbar

breakers-with-busbar.jpg (122.9 KiB)

breaker-detail.jpg (193.9 KiB)

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Modifications Space

Node Red Space

Answer 1 · 2022-03-08T13:00:22Z

klim8skeptic answered · Mar 08, 2022 at 01:00 PM

The terminal would seem to accommodate multiple hex nuts.

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Rob commented · Mar 08, 2022 at 01:37 PM

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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Answer 2 · 2022-03-08T14:52:47Z

airstream-installer answered · Mar 08, 2022 at 02:52 PM

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 commented · Mar 17, 2022 at 08:41 PM

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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Answer 3 · 2022-03-17T20:53:29Z

Phil Gavin answered · Mar 17, 2022 at 08:53 PM

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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Answer 4 · 2022-03-17T21:01:14Z

drlbradley answered · Mar 17, 2022 at 09:01 PM

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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