I'm talking about the bog standard things, sometimes called 'choc
blocks' or terminal strips. I much prefer the ones with wire protectors,
but they seem to be rare. I've found them on the Rapid website and the
CPC website I've and bought some. But since they're so much better why
don't all terminal blocks have wire protectors? The cost difference is
minimal and they remove the danger of the screw cutting the wire.

Bill

You say the cost is minimal but its another piece you need when you make
them. I've never quite understood the basis of just a screw myself as all
too often it just separates stranded wire and the bloomin thing falls to
bits. its The same story as terminals, which do not have any kind of washer
to stop wires coming out the sides.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bill Wright" wrote in message
news
I'm talking about the bog standard things, sometimes called 'choc blocks'
or terminal strips. I much prefer the ones with wire protectors, but they
seem to be rare. I've found them on the Rapid website and the CPC website
I've and bought some. But since they're so much better why don't all
terminal blocks have wire protectors? The cost difference is minimal and
they remove the danger of the screw cutting the wire.

Bill

On Monday, 7 May 2018 07:49:49 UTC+1, Brian Gaff wrote:
You say the cost is minimal but its another piece you need when you make
them. I've never quite understood the basis of just a screw myself as all
too often it just separates stranded wire and the bloomin thing falls to
bits. its The same story as terminals, which do not have any kind of washer
to stop wires coming out the sides.
Brian


That's why you twist the strands up before you insert the cable.
The terminal should be as full as possible (with conductor).

Bill Wright used his keyboard to write :
I'm talking about the bog standard things, sometimes called 'choc blocks' or
terminal strips. I much prefer the ones with wire protectors, but they seem
to be rare. I've found them on the Rapid website and the CPC website I've and
bought some. But since they're so much better why don't all terminal blocks
have wire protectors? The cost difference is minimal and they remove the
danger of the screw cutting the wire.

They are horrible things to use, difficult to get the conductors in
place, but even worse when they become distorted once they have been
tightened.

In article ,
harry writes:
On Monday, 7 May 2018 07:49:49 UTC+1, Brian Gaff wrote:
You say the cost is minimal but its another piece you need when you make
them. I've never quite understood the basis of just a screw myself as all
too often it just separates stranded wire and the bloomin thing falls to
bits. its The same story as terminals, which do not have any kind of washer
to stop wires coming out the sides.
Brian


That's why you twist the strands up before you insert the cable.
The terminal should be as full as possible (with conductor).

There are (in theory) ones designed for stranded wires.
They either have leaf protection springs, or a wide screw
with rounded end that the wires can't squeeze out of.

The other option is to use bootlace ferrules on the strands
and then you can use ones for stranded or solid core conductors.
This is what I normally do for stranded conductors up to 2.5mm2.

For high current with stranded conductors, I use ones which are
suitable for twice the conductor size, and make sure all the
conductors are under both screws.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Mon, 7 May 2018 10:27:52 +0100, "Brian Gaff"
wrote:

Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing to
do in situ.
Brian
That I'm afraid is a definite no no. Some misguided manufacturers
tinned the ends of cables when appliances were supplied plugless.

The tinning used to "flow" away from the point of pressure.

Being cheapskates my company will often provide individual JB,s for
sensors etc and if the spec does not call for it, a chunk of
chockstrip is the norm.

The field wiring is 1.5mm, the sensor can be a few whiskers. Taking
both cables through the connector, so that each one is clamped by both
screws secures things nicely. Bootlaces are fine, but if those are
being used it is easier to go the whole hog and stick a few DIN
terminals in the box along with a short bit of rail.

AB

Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing to
do in situ.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"harry" wrote in message
...
On Monday, 7 May 2018 07:49:49 UTC+1, Brian Gaff wrote:
You say the cost is minimal but its another piece you need when you make
them. I've never quite understood the basis of just a screw myself as
all
too often it just separates stranded wire and the bloomin thing falls to
bits. its The same story as terminals, which do not have any kind of
washer
to stop wires coming out the sides.
Brian


That's why you twist the strands up before you insert the cable.
The terminal should be as full as possible (with conductor).

On Mon, 7 May 2018 10:43:09 +0100, Chris Green wrote:

Brian Gaff wrote:
Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing to
do in situ.

And it encourages the wire to break at the end of the tinning.

For all these reasons I avoid choc-block type terminals wherever
possible.

The other screw-down terminal idiosyncracy that annoys me is where
they have a 'pad' but you can get the wire the wrong side of it so you
carefully put the wire in, tighten the screw and the wire promptly
falls out because it's nut under the grip.

:-)

I often find that some of the effects encountered with faults and
design shortcomings would be near impossible to arrive at if One aimed
deliberately at the "feature".

Some DIN terminals produce this effect. The cable end seems to slide
outside the "box" that clamps the cable yet sits inside the plastic
body. Usually in dark corners of panels where little space has been
allowed between terminal and cable trunking.

Actually I find chockstrip quite good, although I avoid those with
"frills" such as cable protectors like the plauge.

AB

Brian Gaff wrote:
Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing to
do in situ.

And it encourages the wire to break at the end of the tinning.

For all these reasons I avoid choc-block type terminals wherever
possible.

The other screw-down terminal idiosyncracy that annoys me is where
they have a 'pad' but you can get the wire the wrong side of it so you
carefully put the wire in, tighten the screw and the wire promptly
falls out because it's nut under the grip.

--
Chris Green
·

In article ,
Bill Wright wrote:
The cost difference is
minimal and they remove the danger of the screw cutting the wire.

You often find the screw cuts the wire?

--
Is the hardness of the butter proportional to the softness of the bread?*

Dave Plowman London SW
To e-mail, change noise into sound.

On Monday, 7 May 2018 05:41:37 UTC+1, Bill Wright wrote:
I'm talking about the bog standard things, sometimes called 'choc
blocks' or terminal strips. ... The cost difference is
minimal and they remove the danger of the screw cutting the wire.

The cost difference is miniscule on each individual strip, but when you make tens of millions of them a year, a fraction of a penny is thousands of pounds of lost profit on that item.

I have also noticed some "ebay" strips having a lot less metal around the screw than I'm used to, and it's not particularly brassy coloured.

Owain

On 07/05/2018 08:21, Harry Bloomfield wrote:

They are horrible things to use, difficult to get the conductors in
place,
I haven't had a problem.

but even worse when they become distorted once they have been
tightened.
They are a use-once item surely?

Bill

Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned
Any connection can and does work loose. I remember the electrician many
moons ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.
Brian

--
From the Sofa of Brian Gaff Reply address is active
Remember, if you don't like where I post
or what I say, you don't have to
read my posts! :-)
"Archibald Tarquin Blenkinsopp" wrote in
message news
On Mon, 7 May 2018 10:27:52 +0100, "Brian Gaff"
wrote:

Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing
to
do in situ.
Brian
That I'm afraid is a definite no no. Some misguided manufacturers
tinned the ends of cables when appliances were supplied plugless.

The tinning used to "flow" away from the point of pressure.

Being cheapskates my company will often provide individual JB,s for
sensors etc and if the spec does not call for it, a chunk of
chockstrip is the norm.

The field wiring is 1.5mm, the sensor can be a few whiskers. Taking
both cables through the connector, so that each one is clamped by both
screws secures things nicely. Bootlaces are fine, but if those are
being used it is easier to go the whole hog and stick a few DIN
terminals in the box along with a short bit of rail.

AB

On Mon, 7 May 2018 15:53:47 +0100, "Brian-Gaff"
wrote:

Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned
Any connection can and does work loose. I remember the electrician many
moons ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.
Brian

Funny you should say that. I put a 30A ring main into the bungalow
some years back. Fibreglass insulation was given away, so I took full
advantage.

I do think about all those JB's up there and the need to check the
screws, but all that glass and the addition of six stone to yours
truly is a little off putting :-(

On a plus point, the fibreglass is not too flammable, sadly a ceiling
constructed from tongue & groove with umpteen layers of varnish is
probably not the most ideal mounting for JB's

AB

On 07/05/2018 12:16, Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
The cost difference is
minimal and they remove the danger of the screw cutting the wire.

You often find the screw cuts the wire?

It often cuts some of the strands. It's worse with ultra-flexible wires.
Of course some makes have screws with sharp ends!

Bill

On Mon, 7 May 2018 17:24:38 +0100, "dennis@home"
wrote:

On 07/05/2018 15:53, Brian-Gaff wrote:
Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned

They were tinned for test reasons in the factory.
The instructions usually told you to cut them off and they were never
the right length for a plug anyway.

Any connection can and does work loose. I remember the electrician many
moons ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.
Brian


Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

Haven't Airbus UK got a massive order in with Ebay?

Delivery post Brexit :-)

AB

On 07/05/2018 15:53, Brian-Gaff wrote:
Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned

They were tinned for test reasons in the factory.
The instructions usually told you to cut them off and they were never
the right length for a plug anyway.

Any connection can and does work loose. I remember the electrician many
moons ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.
Brian


Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

On Mon, 07 May 2018 18:33:31 +0100, Harry Bloomfield
wrote:

Brian-Gaff formulated on Monday :
Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned
Any connection can and does work loose. I remember the electrician many moons
ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.

It doesn't happen, if the job is done right! They come loose due to
settling. Proper way - Insert cable, tighten a little, waggle the cable
to settle it, tighten some more.

Thank you, I will try that in future.

Bloody obvious with hindsight, I must confess I would never have
thought of doing that though.

AB

Brian Gaff brought next idea :
Should etc, and some wire just seems to come untwisted when flattened. i
guess you could tin the twisted ends but that is not always an easy thing to
do in situ.

You should never tin a conductor to insert it in a screwed terminal.
The solder will settle and turn what began as a good termination, into
a poor one, possibly heating up if it is carrying much current.

Brian-Gaff formulated on Monday :
Yes in hard to reach places tinned ends can squash over time, but a look at
most devices supplied with no plug from back then, most were in some way
tinned
Any connection can and does work loose. I remember the electrician many moons
ago who did this house suggested I tested and tightened all socket and
lightswitch and bayonet screws about a year on from the finish of the job.
many were not as tight as they had been for whatever reason.

It doesn't happen, if the job is done right! They come loose due to
settling. Proper way - Insert cable, tighten a little, waggle the cable
to settle it, tighten some more.

dennis@home submitted this idea :
Screw terminals always work loose which is why they aren't used on important
things. What was the last time you saw chock blocks on aeroplane wiring?

Screw terminals are very common on mains wiring, from a few amps to
thousands of amps. Even crimped lug connections are held on terminals
by nuts and bolts. They do not come loose if they are used properly.
Aircraft do not use them because other methods are easier, quicker,
more reproducible - the difference is the work isn't conducted out in
the field, but under workshop conditions.

On 07/05/2018 12:24, wrote:

The cost difference is miniscule on each individual strip, but when you make tens of millions of them a year, a fraction of a penny is thousands of pounds of lost profit on that item.

That's a common fallacy. It's the cost/benefit per unit that matters.
The amount saved by economies only increases with the number of units.
The benefit gained by not economising increases with the number of units.

Bill

On 07/05/2018 18:40, Harry Bloomfield wrote:
dennis@home submitted this idea :
Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

Screw terminals are very common on mains wiring, from a few amps to
thousands of amps. Even crimped lug connections are held on terminals by
nuts and bolts.

Nuts and bolts aren't screw terminals and they use lugs not wires.
They are significantly different.

In article ,
dennis@home wrote:
Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

If your house vibrates like an aircraft it needs seeing to.

--
*Why does the sun lighten our hair, but darken our skin?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Harry Bloomfield wrote:
dennis@home submitted this idea :
Screw terminals always work loose which is why they aren't used on important
things. What was the last time you saw chock blocks on aeroplane wiring?

Screw terminals are very common on mains wiring, from a few amps to
thousands of amps. Even crimped lug connections are held on terminals
by nuts and bolts. They do not come loose if they are used properly.
Aircraft do not use them because other methods are easier, quicker,
more reproducible - the difference is the work isn't conducted out in
the field, but under workshop conditions.

Screw terminals are used as a cheap and cheerful way of connecting a one
off. No reason to use them on a loom which will be fabricated, as in a car
or aircraft. Also, given the complexity of an aircraft loom, size and
weight could come in to it too.

But you're absolutely right. A properly tightened screw terminal (in a
domestic setting) doesn't come loose. Those that do weren't properly
tightened.

--
*Hard work pays off in the future. Laziness pays off now *

Dave Plowman London SW
To e-mail, change noise into sound.

On 08/05/2018 00:27, Dave Plowman (News) wrote:
In article ,
dennis@home wrote:
Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

If your house vibrates like an aircraft it needs seeing to.


Temperature changes will loosen them over time.
As will road traffic vibrations.

I have even seen corrosion on them due to condensation and wallpaper
paste. Or that's what I thought it was. Once they start to corrode thats
the end as far as screw terminals go, they aren't gas tight like a
proper crimp joint should be.

In article ,
dennis@home wrote:
If your house vibrates like an aircraft it needs seeing to.


Temperature changes will loosen them over time.
As will road traffic vibrations.

Well, I rewired this house when I bought it in the '70s. And have added to
that since.

Still waiting for a terminal to come loose.

I've seen it often on installations others have done, though. Likely an
electrician deliberately making work for the future.

--
*If you think this van is dirty, you should try having sex with the driver*

Dave Plowman London SW
To e-mail, change noise into sound.

Bill Wright wrote:

I'm talking about the bog standard things, sometimes called 'choc
blocks' or terminal strips. I much prefer the ones with wire
protectors, but they seem to be rare. I've found them on the Rapid
website and the CPC website I've and bought some. But since they're
so much better why don't all terminal blocks have wire protectors?
The cost difference is minimal and they remove the danger of the
screw cutting the wire.

Bill

I use these:

https://www.wago.com/gb/installation...onnectors/comp
act-splicing-connector/p/222-413

--


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Monday, 7 May 2018 07:54:43 UTC+1, harry wrote:
On Monday, 7 May 2018 07:49:49 UTC+1, Brian Gaff wrote:
You say the cost is minimal but its another piece you need when you make
them. I've never quite understood the basis of just a screw myself as all
too often it just separates stranded wire and the bloomin thing falls to
bits. its The same story as terminals, which do not have any kind of washer
to stop wires coming out the sides.
Brian


That's why you twist the strands up before you insert the cable.
The terminal should be as full as possible (with conductor).

Problem comes when you have to insert two wires into the same hole that's when it becomes a real pain. Such as when I needed to get the two earths into this.
Why have only 5 connections when you should really have 6.

https://www.screwfix.com/p/lap-24-ho...220-240v/3212r

Think I'll give it a low review later.

On 08/05/2018 08:36, dennis@home wrote:
On 08/05/2018 00:27, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* dennis@home wrote:
Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

If your house vibrates like an aircraft it needs seeing to.


Temperature changes will loosen them over time.
As will road traffic vibrations.

I have even seen corrosion on them due to condensation and wallpaper
paste. Or that's what I thought it was. Once they start to corrode thats
the end as far as screw terminals go, they aren't gas tight like a
proper crimp joint should be.



While I've seen a few screws in plugs work loose etc, I've never seen it
in a light fitting, junction box etc. - at least in a domestic setting.

Crimps are, of course, better- if done correctly. A 'nip' with pliers
isn't correctly ;-)



--

Suspect someone is claiming a benefit under false pretences? Incapacity
Benefit or Personal Independence Payment when they don't need it? They
are depriving those in real need!

https://www.gov.uk/report-benefit-fraud

Ashley Booth wrote:

Bill Wright wrote:

I'm talking about the bog standard things, sometimes called 'choc
blocks' or terminal strips. I much prefer the ones with wire
protectors, but they seem to be rare. I've found them on the Rapid
website and the CPC website I've and bought some. But since they're
so much better why don't all terminal blocks have wire protectors?
The cost difference is minimal and they remove the danger of the
screw cutting the wire.

Bill

I use these:

https://www.wago.com/gb/installation...-connectors/co
mp act-splicing-connector/p/222-413

https://tinyurl.com/y73sfoou

--


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

In article ,
"dennis@home" writes:
On 08/05/2018 00:27, Dave Plowman (News) wrote:
In article ,
dennis@home wrote:
Screw terminals always work loose which is why they aren't used on
important things. What was the last time you saw chock blocks on
aeroplane wiring?

If your house vibrates like an aircraft it needs seeing to.


Temperature changes will loosen them over time.
As will road traffic vibrations.

I have even seen corrosion on them due to condensation and wallpaper
paste. Or that's what I thought it was. Once they start to corrode thats
the end as far as screw terminals go, they aren't gas tight like a
proper crimp joint should be.

They are gas tight if assembled correctly - the contact pressure
of a through-hole terminal is many times than of a crimp, which
is why the copper deformation is many times higher. The contact
pressure of a wrap-around screw terminal is same order as a
crimp.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]