Wire Crimping

What size are you using?

Most often, the only reason for more then one wire into a lug is used on permanent fixture wiring which its expected life span is towards an ultimate doom and total distruction of item. Under normal electrical practices, one wire per lug! The thought of bunching more then two leads into one lug is by far the worst kind of deliberate insuffiency being created due too laziness. If you look at your common automobile battery terminals, you might find up to two wires connected on one lug. If you look closely, you will notice the oxidation build up, this is due to a loose connection. If you put more then one wire on a terminal lug, you will never have proper compression for a reliable crimp on your wire. The laws of physics will prove a fatel discomfort if more then two wires are compressed into a single wire space. Take three wires, a prime number with an equivical surface area of each wire. Mind you, these are single strand wires being used, the compression factor of the lug will be close to equal terms, only if you used a four way crimping tool. If you use a standard two directional crimping tool, only two of the three wires will have neer equal compression, leaving the third wire loose in the lug. If you must have more then two wires in one lug, your only safe step, is to solder your connection. This is a general practice in most high tech environments. Now, if you are useing multi-strand wire, your compression factor error is multiplied by the number of added strands of wire -2. The minus 2 is for the safe factor of equal compression on your wire. Even at only two leads into a single lug space, there is a major verience in compression depending on what type of tool is being used to crimp the wires. And as mentioned before, if you use two leads with stranded typw wire, the compression factor is displaced by the number of strands. And to make this even more of a error, if one lead is a solid single strand and the other lead is a miltiple strand type wire. Much to the worst, is if you use dissimular wire sizes. Then your margin of error for failure in the crimp is multiplied by 2 times the number of strands of dissimular wire combinations being used. So actually know the safe number of leads into a wire lug, the answer is one per lug and the use of the proper gauged lug for the wire being crimped. Even if you use one lead with multi-strands, you have a margine of error if the wrong lug is used for the wire. If you use a lug that is too small for your wire, you take the chances of cutting off some of your strands which in turn has just created a weak point in your electrical path. In turn this just created an electrical harmonics problem. Good luck.

Seems like too much analysis for the grouping of shields. If the location is under A/C should not have much oxidation problem. You want a good connection, so I would not want more than 5 or 6 shields together. Pick a crimp lug that will accomadate that number, do 4 or 5 test crimps doing a good pull test. After the final crimp, maybe a low resistance test shield to shield. I know much to low level engineering. Don't do this for air bourne systems. Not man rated.

As far as I know that all the cable lug have a standard wire size for example; 1.5mm cable lug is for 1.5 mm cable size, 2.5 mm cable lug for 2.5 mm cable size and so on...... Unless you use some bigger size cable lug for smaller wire and clip all the cable in to one cable lug. Clamping of the cable or the cable shields be crimped into a single grounding lug is not a very good idea. This is because when you want to removed out the cable for some other reason for example; electrical checking or do some resistance measurement during the breakdown, you will need to cut off the cable from the clamp cable lug for such propose and the other problem that may encounter is that by clamping all the cable shields into a single grounding lug is not a very good pratice beacuse if the cable lug is having a bad contact to the grounding bar the rest of your grounding shields will be affected.

This reply and those above are well thought out. From a contact conductivity point of view the type of crimper and lug has a major bearing on the outcome. For instance when looping a common conductor between tunnel terminals using flex, securing the loops in a bootlace ferrule which is crimped with an approved indent crimper to the correct pressure can be shown to improve the system reliability (double ferrules are manufactured for just this purpose). This is achieved by maintaining the continuity of the loop unless deliberately parted and by providing a long tight common bond. Tunnel connectors can become unreliable when two or more seperate conductors are inserted. Where more than one conductor is inserted into a lug use either a Hydraulic Hex Die or an Indent Crimper for reliability. The flat crush type crimper gives the poor and uneven contact pressure so well described in one of the earlier replies. Slightly off the beam here, the difference that even invisible oxides make to the finished quality of a crimp joint,even when crimped with a specialised 23 tonne hex die, has to be seem to be believed (using a micro-ohm meter), so keep it clean.