DIY Fuse Holders and Distribution Busbars

[DerpsyDoodler]

I'm not following this, what do you mean by fusing each B+ post-bms, the BMS (if inline) generally would be on the negative side. Are you using a BMS with external control (relays)?

Yes, Chargery; and the DCC contactors [edit: assuming I go with chargery’s DCCs] will be on the positive leads with iso boards.

edit: actually, fuses will go pre-DCC. I think that makes more sense.

 

[DerpsyDoodler]

Is there a standardized or recommended spacing between studs on a bus bar?

 

[ArthurEld]

Is there a standardized or recommended spacing between studs on a bus bar?

Enough space to use a wrench minimum. Maybe there is a standard like 4 times the bolt diameter between holes

 

[ArthurEld]

I am thinking of ways to make covers for busbars and fuse holders. I like clear plastic but it mainly needs to improve safety.
One concern is heat so the cover should allow good air flow.

 

[DerpsyDoodler]

Enough space to use a wrench minimum. Maybe there is a standard like 4 times the bolt diameter between holes

Hmm, would I consult abyc or nec. I am thinking nec. I would like to be able to avoid this deep dive, but it is the cost of DIY. Aside from that, it’s an absolutely worthwhile time investment, anyway. Just not my favorite part of DIY.

 

[ArthurEld]

Hmm, would I consult abyc or nec. I am thinking nec. I would like to be able to avoid this deep dive, but it is the cost of DIY. Aside from that, it’s an absolutely worthwhile time investment, anyway. Just not my favorite part of DIY.

I assume newest rules require UL busbars and fuseholders.

 

[DerpsyDoodler]

I’d thought about that. How does that apply to RVs? I’m fine with not being fully compliant with portions I do myself, as long as I make it conform to the safety standards intended. It’s not like I am a professional conversion outfit doing this as a business. What other ways might this decision affect me?

 

[Hedges]

I am thinking of ways to make covers for busbars and fuse holders. I like clear plastic but it mainly needs to improve safety.
One concern is heat so the cover should allow good air flow.

Where cables join batteries in series, I have exposed bolts and ring terminals. I put a lid of corrugated plastic roofing over the battery.

I just replaced hoses on my truck, and cut 1/2 or 5/8 hose into pieces a few inches long. Split lengthwise they close over the cable and splay out enough to cover terminals. Plan to add cable ties to secure them better.

How about a length of grey plastic conduit, drilled to let cables fit (if connected orthogonal) and sawn lengthwise so it can fit over busbar or fuseholder?

If you're using those Bussmann fuse holders, could drill bottom half of split cover and bolt fuse holders to it.
Optionally, tall plastic threads could serve to attach top half.

 

[ArthurEld]

I’d thought about that. How does that apply to RVs? I’m fine with not being fully compliant with portions I do myself, as long as I make it conform to the safety standards intended. It’s not like I am a professional conversion outfit doing this as a business. What other ways might this decision affect me?

I measured an expensive 5/16" busbar and it is about 4 times the diameter between studs.

 

[Hedges]

I measured an expensive 5/16" busbar and it is about 4 times the diameter between studs.

The busbar I bought had larger spacing than that, but not enough for my ring terminals (well, maybe I drilled larger for my bolts.)
Start with what you need to fit on it and work backwards. You can fit more in a shorter busbar if spacing is just enough to fit rather than not quite enough.
Measure twice, then make it longer. Better to leave extra length for future additions, rather than having to make a new busbar.
I suppose I could fit smaller cables/terminals on the holes I had to skip over for 2/0 terminals.

 

[ArthurEld]

Where cables join batteries in series, I have exposed bolts and ring terminals. I put a lid of corrugated plastic roofing over the battery.

I am still working on a cover for the whole battery. I could enclose my shelves too.

I just replaced hoses on my truck, and cut 1/2 or 5/8 hose into pieces a few inches long. Split lengthwise they close over the cable and splay out enough to cover terminals. Plan to add cable ties to secure them better.

How about a length of grey plastic conduit, drilled to let cables fit (if connected orthogonal) and sawn lengthwise so it can fit over busbar or fuseholder?

If you're using those Bussmann fuse holders, could drill bottom half of split cover and bolt fuse holders to it.
Optionally, tall plastic threads could serve to attach top half.

I saw some cheap fuse covers that looked adaptable. I think there may be a type of plastic sheet that is formable that might work.
The hoses and conduit sound good.

 

[DerpsyDoodler]

I’d thought about that. How does that apply to RVs? I’m fine with not being fully compliant with portions I do myself, as long as I make it conform to the safety standards intended. It’s not like I am a professional conversion outfit doing this as a business. What other ways might this decision affect me?

I need to clarify that. I’m fine with not being UL compliant for a component that I DIY myself (and am aware this will mean I don’t meet the abyc standard). How will not being compliant to the ABYC standard affect me?

 

[Hedges]

I need to clarify that. I’m fine with not being UL compliant for a component that I DIY myself (and am aware this will mean I don’t meet the abyc standard). How will not being compliant to the ABYC standard affect me?

If your RV falls in the water and is not in compliance, the coast guard might cite you.

 

[DerpsyDoodler]

If your RV falls in the water and is not in compliance, the coast guard might cite you.

? yeah...after I asked the question, I started doing some digging around...lol. don’t want to track the discussion further of course so I’ll just cross link this thread in case someone is interested in the topic.

Thread 'We have the NEC code for residential electrical, ABYC standards for marine electrical, is there an equivalent for mobile/vehicle/rv electrical?'
https://diysolarforum.com/threads/w...valent-for-mobile-vehicle-rv-electrical.5587/

 

[HRTKD]

RVIA may have some guidelines for the DC part of the system. However, given the loosey goosey nature of these RV manufacturers, just because there is an RVIA sticker on the outside of the trailer, doesn't mean they actually followed any standards.

I'm still trying to figure out how some of my RV's loads are fused. They sure aren't fused on the main distribution panel. I can pull every fuse on the panel and some things still work.

 

[DerpsyDoodler]

hmm, would be interested to learn why. Have you tried reaching out to the mfg to see what they say?

 

[FilterGuy]

I can pull every fuse on the panel and some things still work.

What loads?

I know on at least some Airstreams they bypass the distribution panel for the LP Gas detect, the Emergency Break and the Toung jack.
I suspect this is because they have a Disconnect between the battery and the Distribution panel and they want those 3 items to work even if the disconnect is in the off position.

You see similar situations on boats..... As a example, the sump pump is often on it's own critical circuit that is not easily disabled.

 

[FilterGuy]

What loads?

I know on at least some Airstreams they bypass the distribution panel for the LP Gas detect, the Emergency Break and the Toung jack.
I suspect this is because they have a Disconnect between the battery and the Distribution panel and they want those 3 items to work even if the disconnect is in the off position.

You see similar situations on boats..... As a example, the sump pump is often on it's own critical circuit that is not easily disabled.

BTW: on the airstream, the 3 seperate loads have fuses near the battery.

That brings up another point. If the loads that you can't find the fuses for don't have fuses near the battery, it sounds pretty dangerous. Even if there is a fuse near the load, a short before the fuse would create a lot of toxic smoke as the wire insulation burns and as it gets hotter, it becomes a fire danger.

 

[HRTKD]

hmm, would be interested to learn why. Have you tried reaching out to the mfg to see what they say?

Ha! Not going to happen. They went bankrupt about three years after my trailer came off the line.

What loads?

I know on at least some Airstreams they bypass the distribution panel for the LP Gas detect, the Emergency Break and the Toung jack.
I suspect this is because they have a Disconnect between the battery and the Distribution panel and they want those 3 items to work even if the disconnect is in the off position.

You see similar situations on boats..... As a example, the sump pump is often on it's own critical circuit that is not easily disabled.

Air compressor, generator, generator fuel pump, fueling station, HappiJac bunk bed, search light, water heater. This my current list of unknowns. The generator is kind of obvious since it draws so many amps. It sure isn't going through the main distribution panel. But I haven't found a fuse or circuit breaker on the DC side for it.

 

[FilterGuy]

They went bankrupt about three years after my trailer came off the line.

Hmmmm... the trailer had weird, potentially dangerous wiring that might result in lawsuits.... Could there possibly be a connection?