Copper Bus Bar 1 metre 1500A

Two numbers matter, the cable and the eye size. The lug is named by the cable it takes: 4, 16, 35, 50 or 95 mm2. Match it to the cable you are actually terminating, not to the current, because the copper has to fill the barrel of the connector properly for the crimp to hold.

Then pick the eye size for the bolt you are using. The 4 mm2 is M4 only. The 16 mm2 comes M6 or M8, the 35 mm2 M6, M8 or M10, the 50 mm2 M8 or M10, and the 95 mm2 M8, M10 or M12.

The current ratings follow the size: 16 Amps on the 4 mm2, then 100, 150, 200 and 400 Amps as you go up.

They are sold singly, so count your ends. A cable with a lug on each end is two.

See the full AWG to mm2 conversion chart

The first number is what the terminal will carry all day. The second is what it will carry when it is only working part of the time, 60% on and 40% off, because the copper gets a chance to shed the heat in between.

A winch, a starter motor or a welder is a duty cycle load. An inverter running a house, a fridge or a charger is not, that is on and it stays on.

If you are not sure which you have, size on the continuous figure. Getting it wrong the other way gives you a hot joint, and a hot joint gets worse by itself: the resistance rises as it heats, which makes it hotter again.

Crimp, if you have the tool for the size. A proper crimp is a gas tight joint, the copper is cold welded together and there is nothing in there to soften.

Solder is fine and plenty of people do it, but the solder wicks up the strands above the barrel and turns flexible cable into a stiff rod at exactly the point that gets vibrated. On anything in a vehicle or a boat that is where it eventually breaks.

If you do solder, keep the heat and the solder in the barrel and don't let it run up the cable.

Our terminals take either. They are pure electrical copper with a tin coating, so they solder easily and crimp well.

Pick by cable first. The 50A takes 1.3 to 8.3 mm2, the 175A takes 25 to 110 mm2, and the 350A takes 60 to 130 mm2. All are rated to 600V.

They are genderless. Both halves of a connection are the same part, so there is no male end and no female end to get wrong, and a spare fits either side.

The colours are a keying system, not decoration. The housings are moulded so a grey will only mate with a grey and a red only with a red, which is how you stop two different systems being plugged into each other by mistake. So order both ends the same colour. Our 50A and 175A are grey, the 350A is red.

Stack two and you will probably get away with it. Stack four that are all carrying significant current and you have built yourself a problem.

A bus bar gives every cable its own post. One joint each, all the same, all reachable. The 150A does 150 Amps at 48V DC on four M8 and six M4 posts, so the M4s take your small stuff, the fused feeds and the monitoring. The 300A does 300 Amps at 48V on four M8 posts, with a blank label on the lid to write what each one feeds, which you'll want in two years when you have forgotten.

If you need more than that, there is a metre of solid copper bar, 30 mm by 5 mm, good for 1500 Amps, and you drill it to suit and build your own.

Because they do a different job. They are 4.5 mm thick pure electrical red copper, they come as a matched pair rather than singly, and the barrel is closed at the end so damp and dirt can't get into the cable.

The narrow body is the whole point. It gets two cables onto posts that sit close together, or into a housing where a standard lug won't turn. If you have the room, the standard lug is the less expensive option and it isn't worse.

Both sizes, 70 mm2 and 95 mm2, are 400 Amps continuous.