"Who did this gland ?" - soldering my banjo ...

frank999 · 25 Oct 2020

My electrician drew my attention to some SWA termination going into metal enclosures ... in a dimly lit and unfinished outbuilding he asked ... "who did this gland ?"

An earth cable was soldered to the banjo, my Electrician has insisted the earth cable be crimped to a round hole lug and an M4 brass bolted connection made to the banjo instead, using brass nuts, bolts and washers.

What are the mechanics that make soldering unacceptable in this situation(according to my sparky).

Mains wires in some appliances terminate on a soldered circuit board ... what is the logic.

Is there ever a scenario where the solder would melt ?? or is there something in the conductivity of a soldered connection, as opposed to the brass.

RF Lighting · 25 Oct 2020

Assuming the wire is the correct size, then nothing wrong with soldering at all.

Perhaps he’s one of those “electricians” who has the mindset of “I don’t do it like that so it must be wrong” or he doesn’t know soldering so it must be wrong.

As a side note I would have thought M4 was too small.

JohnW2 · 25 Oct 2020

frank999 said:
An earth cable was soldered to the banjo, my Electrician has insisted the earth cable be crimped to a round hole lug and an M4 brass bolted connection made to the banjo instead, using brass nuts, bolts and washers. ... What are the mechanics that make soldering unacceptable in this situation(according to my sparky).

There's nothing wrong with soldered electrical joints, per se, BUT ...

frank999 said:
Is there ever a scenario where the solder would melt ??

As I understand it ... the soldering of an electrical joint is only ever meant to keep a 'mechanical joint' secure. Hence, in a situation such as you describe there would have to be a 'mechanically satisfactory joint' between the conductor and the banjo before soldering (e.g. with the conductor passing through a hole in the banjo and then being twisted/knotted/whatever).

If one just lays the conductor against the banjo and then solders them together, so that the solder is the only thing maintaining the joint, then that is not satisfactory/acceptable.

Kind Regards, John

SUNRAY · 25 Oct 2020

Well...

The current running through a joint will heat it. However if the installation has been designed and built correctly it should not. If it did get hot enough to melt a soldered joint I think there will other, and possibly more serious, issues well before that happens.

Soldered joints are not permitted in lightning protection systems due to the huge currents discharged in them.

What size earthwire are you talking about? I would usually expect to see M6 as a minimum.

ericmark · 25 Oct 2020

Soldered butt connections can fail where solder cracks, but a wire connected by twisting and then wetted with solder is OK it is down to solder cracking, and with two way radio's I looked after the solder to aerial socket was for ever cracking and we would need to remelt the solder.

333rocky333 · 25 Oct 2020

As above never seen a banjo with less than 6mm hole and getting 4mm brass bolts from an electrical wholesalers is nigh on impossible, M4 pan head brass machine screws are more common

SUNRAY · 25 Oct 2020

333rocky333 said:
As above never seen a banjo with less than 6mm hole and getting 4mm brass bolts from an electrical wholesalers is nigh on impossible, M4 pan head brass machine screws are more common

Yes. But I've seen a few banjos done with M4 panheads and very frequently BZP. Big head self drills are also not uncommon. Just remember a lot of people think a screw is a wood screw or self tapper and anything with a 'machine' style thread is a bolt.

SUNRAY · 25 Oct 2020

ericmark said:
Soldered butt connections can fail where solder cracks, but a wire connected by twisting and then wetted with solder is OK it is down to solder cracking, and with two way radio's I looked after the solder to aerial socket was for ever cracking and we would need to remelt the solder.

Seems like we share a few T-Shirts.

ericmark · 25 Oct 2020

SUNRAY said:
Seems like we share a few T-Shirts.

VP8XBHZ, VP8BKM, GW7MGW and VR2ZEP is that what you mean?

frank999 · 26 Oct 2020

... Pan Head Screws, sorry ... it should have read that ...

M6 ???? sourcing Brass screws, nuts and washers was quite difficult - in M4, would the Round Hole Lug size not dictate the diameter of the threaded clamp, but yes get the logic of a larger size.

The SWA is 2.5mm², but 4mm earth cable has been used, some strands will be cut off so it can be accomodated in the crimp lug.

So a soldered connection could deteriorate over time ?

winston1 · 26 Oct 2020

frank999 said:
So a soldered connection could deteriorate over time ?

It shouldn’t if done properly. Soldering is a long established skill used in the electronics industry and by plumbers.

Harry Bloomfield · 26 Oct 2020

frank999 said:
My electrician drew my attention to some SWA termination going into metal enclosures ... in a dimly lit and unfinished outbuilding he asked ... "who did this gland ?"

An earth cable was soldered to the banjo, my Electrician has insisted the earth cable be crimped to a round hole lug and an M4 brass bolted connection made to the banjo instead, using brass nuts, bolts and washers.

A soldered joint to be acceptable needs to be (before the solder) mechanicially sound. If it meets that criteria then I would consider soldered a step up and more acceptable than a purely mechanical joint, using bolts and crimped cable lugs.

Note - I certainly would not accept a solder tinned wire end into a crimped lug, or in a terminal, or trapped under a nut and bolt. Solder tends to migrate under pressure, eventually producing a poor termination.

333rocky333 · 26 Oct 2020

frank999 said:
... Pan Head Screws, sorry ... it should have read that ...

M6 ???? sourcing Brass screws, nuts and washers was quite difficult - in M4, would the Round Hole Lug size not dictate the diameter of the threaded clamp, but yes get the logic of a larger size.

Sometimes on ebay you see, the brass bolts, nut and 2 washers as a set.
Similar but i like a washer each side personally.
https://www.ebay.co.uk/itm/BRASS-Se...040016&hash=item21406b3009:g:XwMAAOSwlCdbDoSl
Yellow lugs claim to be for 4mm and 6mm, though with a cheap crimper it could be a bit loose on 4mm.
Lug holes are sized roughly 4.3mm 5.3mm 6.3mm plus others
M4 even with a 4mm lug hole will fit poor on a banjo but it does get done sometimes, m4 washers will barely cover the 6mm banjo hole.

frank999 · 27 Oct 2020

M4 even with a 4mm lug hole will fit poor on a banjo but it does get done sometimes, m4 washers will barely cover the 6mm banjo hole.
Curses - so back to the drawing board.

Note - I certainly would not accept a solder tinned wire end into a crimped lug, or in a terminal, or trapped under a nut and bolt
Its dead end road then ??

Is there an exact clause of the Wiring Regs that gives guidance as to the correct connection method of an earth wire to 4 core SWA terminated gland banjo.

I can solder a good copper pipe connection for sure ...

chivers67 · 27 Oct 2020

M6 Nut, Bolt & Washer 6mm Earth wire with Yellow Ring Crimp was the standard stuff I used doing 6mm SWA. Would have thought soldering Brass Banjos not too easy

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"Who did this gland ?" - soldering my banjo ...

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