do crimped ferrules increase resistance

[John Frum]

Do ferrules make a lower or higher resistance connection?

 

[SCClockDr]

I believe no increase. Now to test that theory. I have that system & can crimp on a few to test against bare copper.

 

[Steve_S]

The simple answer is, every connection, can increase resistance. It is usually very minimal, unless it is a bad / poor connection to begin with. Soldering some connections (like the leads for the BMS & ferule) can reduce it but again, it is millivolts not volts. Good crimps make for good connections and lowers resistance introduced.. BTW I always put a small shrink wrap over the barrel after crimped, for clean & tidy connectors and making sure that there is no stray filament dangling about. It's just the electronics training I got from the military, may be over kill but I don't mind that.

 

[nosys70]

stranded wire contains a lot of air (an isolant) especially when the plastic around is removed.
usually correctly installed ferrule should be thight enough to compress the wire enough to make it like solid.
on the other hand, ferrules are usually round, when contact slot a square, with a pressing blade. this would make contact only on a small
zone of the ferrule. without ferrule, the wire would crush getting a better contact surface.
So eventually a ferrule would be more efficient if it is flat on the side were it touch the contacts.
we are speaking about mili ohms here so i doubt you can really make a difference between one type of contact versus the other one.

 

[John Frum]

The ones in the linked url turn out square and corrugated for added surface area.

 

[nosys70]

ok , so that's the best you can get.
unfortunately the tool in the link go up to 10mm2, only , that is pretty small when you deal with DC in solar systems.
it pretty common to get sizes like 30mm2 up to 100mm

 

[John Frum]

ok , so that's the best you can get.
unfortunately the tool in the link go up to 10mm2, only , that is pretty small when you deal with DC in solar systems.
it pretty common to get sizes like 30mm2 up to 100mm

I have seen larger larger ferrules, mostly used in car audio.
Those ones are not crimped the same way though.

 

[nosys70]

possibly you can use a round ferrule ans solve the problem with a big hammer

 

[KG6S]

I think that a properly crimped quality ferrule is actually superior to a bare wire in applications where the bare wire is torqued in a terminal. A good quality copper wire (strand) can cold flow and caused increased resistance unless re-torqued on a periodic basis -- one reason why I check torque on my whole-house gen-set transfer gear every six months.

On the other hand, a quality ferrule and crimp will mash the copper together along with the ferrule into a solid metal mass preventing cold flow of the copper.

I use these higher gauge ferrules and crimp tools on 10 AWG wires and thinner:

Wire Ferrule Starter & Mini Kits | Ferrules Direct

Ferrules Direct newly developed essential starter kits contain a wide variety of our single insulated wire ferrules in huge quantities.

www.ferrulesdirect.com

Copper clad aluminum cable is a fire waiting to happen in any event. Too many issues to get into in this forum. (Hopefully no one here is using CCA!)

 

[HRTKD]

Will a ferrule for 6 awg wire, fit into an opening that is expecting 6 awg wire? In other words, are the crimped ferrules larger than the wire? I don't see how they could be the same size, but maybe there's some magic going on.

The reason I'm asking is that I have 6 awg wire that will be coming out of my breakers and going into my Victron 100/50. If I put a ferrule on the 6 awg wire, will it still fit in the Victron?

I'm finding plenty of ferrule crimpers for small wire, but not many for larger wire, like 6 awg. FerrulesDirect.com helped me find size appropriate crimpers, but I haven't bought anything yet. Still researching...

 

[John Frum]

In my experience the ferrules add to the size a bit.
Unless you are using the largest size that the mechanical lug is designed for it won't be an issue obviously.
I don't know about 6 awg because the smallest mechanical lug that I could land to allows 4awg max.
I do know that wago 221-61x lever nuts won't accept 10 awg stranded with a crimped ferrule.
For mechanical lugs that won't accept a crimped ferrule sometimes you can use an uncrimped ferrule and let the mechanical lug do the "crimp".
This is what the car audio guys do.

 

[Zil]

Any device of mine that has "crush the wire" terminals the manufacturer recommends using ferrules. I think the quality depends on the quality of the ferrules and the tool used to crimp them. HF is not your friend with this.

 

[HRTKD]

I think I might be OK with 6 awg ferrules. The Victron spec for the 100/50 calls for wire that is "16 mm² / AWG6". 6 awg has an area of 13.3018. Since that is smaller than 16 mm² there may be room for the ferrule.

I guess I'll find out the hard way. I ordered a ferrule crimper and a kit of ferrules. I'm a sucker for new tools.

 

[JoeHam]

Do ferrules make a lower or higher resistance connection?

I would argue that they can make a lower resistance connection.

I base that on my study with n=1 on YouTube where someone had stranded wire in a screw terminal that really lit up on a thermal image. He then crimped a ferrule on, rescanned while running the same current through it and the hotspot was gone. The difference was dramatic.

Although, n=1

Edit: I was thoroughly impressed enough to buy this setup which looks much like your link:

Amazon.com

I have since crimped all feral connections with ferrules and am happy with the results (see what I did there).

 

[HRTKD]

I have since crimped all feral connections with ferrules and am happy with the results (see what I did there).

Besides being a Photon Sorcerer, you're a Word Wizard too?

 

[John Frum]

Just noticed the plastic bit on my shoelace is a bit gnarley.
Got an idea, hold my beer.

 

[HRTKD]

Conductive shoelaces? Maybe not your best idea.

 

[John Frum]

Conductive shoelaces? Maybe not your best idea.

That is why my feet will have to be grounded. :|

 

[HRTKD]

That is why my feet will have to be grounded. :|

I see some hobnail boots in your future. Welcome back to Roman times.

Anyhow, this article talks at a high level about ferrules. The reader comments are almost more educational. They REALLY don't like soldering/tinning the ends of wires!

To Ferrule Or Not To Ferrule?

We recently posted about a spectacular 3D-printer fire that was thankfully caught and extinguished before spreading to the hacker’s house or injuring his family. Analyzing the remains of the …

hackaday.com

 

[Zil]

Just noticed the plastic bit on my shoelace is a bit gnarley.
Got an idea, hold my beer.

A long time passing, the backpack camper stores would make boot laces from 'parachute cord' with heat shrink for the ends.