Ok to attach more than one cable per stud in Lynx busbar?

[jameshowison]

I'm confused about whether it's ok to attach more than one wire to each stud in the Lynx busbar? There seem to be "wire separator" pieces of plastic (which the manual talks about removing).

Seems the general position on this is "try not to have too many on a single stud, definitely not more than four"? (The four per stud coming from the ABYC regs). Any guidance on doing it reasonably? I can't find any pictures like that.

I'm not using any fuses inside the box, it's the Lynx power-in, not the distributor. On the positive side I need (2) 2 AWG (battery, inverter) and (4) 12 AWG or higher (2 MPPT, 1 Orion 48-12 converter, 1 30amp HVAC), so 6 in total (4 connection points, 6 if you use the end holes).

On the negative side I need each of those 6, but I also need Chassis ground (2 AWG) and grounds for the inverter and each of the four loads. So that's 12 cables. There is an extra stud on the negative side.

I guess this question is not really specific to the Lynx, but really any busbar (assuming sufficient amps).

 

[rmaddy]

For general bus bars 2 lugs per stud is fine. Some say 3 is OK. I'm not sure what limit the Lynx Power-in has but it looks like you can only fit one positive and one negative wire per location. Victron also sells regular bus bars.

Keep the following in mind:

- The lugs must stay flat and maximize contact.
- Put the lugs for the wires with the highest amps on first. Then put lugs for wires with lower amps on second.
- Also ensure that you do not put physically larger lugs on top of physically smaller lugs.
- Ensure the nut can be screwed on enough so at least one thread shows when properly torqued. If you can't get one thread showing then there are too many lugs on that stud. Don't over tighten the nut just to get the one thread to show.

 

[Alloy]

Flipping the first lug on the terminal upside down allows two lugs to come in from the same place with out bending the lug.

 

[jameshowison]

Ah, because Lynx has cables coming from same direction, so to stack them you flip one.

Makes sense!

I can see that would limit things to two per stud but that is enough, I think. Some diagrams have the ground from the MPPT stacked in the inverter grounding spot as well, so that could free up space.

 

[Alloy]

Ah, because Lynx has cables coming from same direction, so to stack them you flip one.

Makes sense!

I can see that would limit things to two per stud but that is enough, I think. Some diagrams have the ground from the MPPT stacked in the inverter grounding spot as well, so that could free up space.

You may need to add a bus bar or a stud terminal

 

[jameshowison]

Ah, I finally found a picture with more than two wires, looks like they just offset the ring terminal connects by 20-30°.

https://community.victronenergy.com/storage/attachments/26381-img-4581.jpeg

 

[c&g]

I was told on the Victron Powered Camper Facebook ground that you can't double up on the studs.

I was trying to deal with 2x50mm cables coming from the 12/3000 multi plus and they mechanically also couldn't fit into the lynx. Ice now ordered a thicker cable.

 

[jameshowison]

Running into issues with this for 10 AWG wire. I'm using insulated heat shrink ring terminals from DelCity. The crimped part (and the insulation) run into each other. See pics.

Any suggestions? 10 AWG seems very hard to do with the style of compression lugs in the picture above. Perhaps these long nosed non-insulated ones: https://www.delcity.net/store/Non!Insulated-Long-Neck-Ring-Terminals/p_823561.h_809002

 

[corn18]

Running into issues with this for 10 AWG wire. I'm using insulated heat shrink ring terminals from DelCity. The crimped part (and the insulation) run into each other. See pics.

Any suggestions? 10 AWG seems very hard to do with the style of compression lugs in the picture above. Perhaps these long nosed non-insulated ones: https://www.delcity.net/store/Non!Insulated-Long-Neck-Ring-Terminals/p_823561.h_809002

I had a similar issue so I just trimmed the heat shrink back where it crossed so all the metal would lay flat. You really don't need the heat shrink inside the Lynx as the cover will protect it. Although it looks like yours is really thick so it may provide some strain relief.

 

[timselectric]

Best practices are to bring all conductors to a separate buss bar and then a single conductor to the piece of equipment.

 

[jameshowison]

I had a similar issue so I just trimmed the heat shrink back where it crossed so all the metal would lay flat. You really don't need the heat shrink inside the Lynx as the cover will protect it. Although it looks like yours is really thick so it may provide some strain relief.

Hah, I think that did the trick. I guess I thought it was the crimp part causing the interference but it was the heat shrink. Definitely wouldn't get more than two on there though

 

[timselectric]

That looks fine.

 

[jameshowison]

Technically you can do this, but it is not smart.

You have a fuse connected to two separate conductors. There should be one conductor for each overcurrent protection device.

On a fuse block, you have one conductor for each fuse.

If you are connecting random ground cables to a single lug, you can add 2-3. I believe ABYC limit is 3 per lug.

Thanks. This is a Lynx Power In, being used as a bus bar.

These are the negative and the grounding wire (going to be green wire, hasn't arrived yet so prototyping with two black wires), would just be a single positive cable. I thought it was neater to do both the negative and the ground for one piece of equipment on the same post, rather than gathering the ground wires onto a single post. Any reason to prefer one to the other?

As it happens, there aren't any fuses on these, over current protection via a DC rated circuit breaker. This is because it's a 48v system and there are no 58v Maxi fuses with low enough amp ratings to use here. Decided against trying to fit the 58v midi fuses in here. Probably I could use a different bus bar approach and it would be cheaper but already have the Lynx and so many of the bus bars aren't rated for 58v+

 

[corn18]

So in my diagram, I have the DC loads going to the distro panel (6ga @ 3') and the front DC loads (8ga @ 6') going to the same fuse on the Lynx (3rd fuse from left on Lynx). The wires to both loads can easily handle 60A, so why is there an issue with hooking them to the same fuse? All the wires are protected within their ratings. The total load on that fuse will never exceed 60A unless something malfunctions, so I have enough fuse to protect the wires and I have enough fuse to not nusiance trip.

I guess I could have 18A coming into that fuse from the truck and 78A going out to the DC distro panel, but that 6ga wire can easily handle 78A.

 

[timselectric]

This seems acceptable, in your situation.
Would rather see #6 for both wires.

 

[jameshowison]

So in my diagram, I have the DC loads going to the distro panel (6ga @ 3') and the front DC loads (8ga @ 6') going to the same fuse on the Lynx (3rd fuse from left on Lynx). The wires to both loads can easily handle 60A, so why is there an issue with hooking them to the same fuse? All the wires are protected within their ratings. The total load on that fuse will never exceed 60A unless something malfunctions, so I have enough fuse to protect the wires and I have enough fuse to not nusiance trip.

I guess I could have 18A coming into that fuse from the truck and 78A going out to the DC distro panel, but that 6ga wire can easily handle 78A.

View attachment 86056

Nice diagram! Where are you grounding the MPPTs?

 

[corn18]

Nice diagram! Where are you grounding the MPPTs?

I haven't yet. Need to do that. They are mounted right next to my frame so I will probably just run an 8ga bare copper wire right to the frame.

 

[HRTKD]

You can pick up ground bus bars from HD for cheap. My only advice on these are to get one with large enough terminal holes for larger gauge wire if you think you'll need it. And don't bury the ground bus bar behind your batteries like I did. Once I installed my batteries I can sort of see the bus bar but I can't access it. It sounded like a good idea at the time.

Square D 7 Terminal Ground Bar Kit for QO/Homeline Electrical Panel/Load Center(PK7GTACP) PK7GTACP - The Home Depot

The Square D by Schneider Electric Ground Bar Kit is an important accessory in your home or business electrical load center. This 7 Terminal Ground Bar Kit is used in load centers, CSED devices and NQOD

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