On Sat, 3 Mar 2007 16:36:19 -0000, JohnDW
wrote:

Peter Bennett, in article 0inhu2helpvoua2dr1h3ekkopfsr67qjp1
, says...
On Fri, 2 Mar 2007 16:05:36 -0800, "Lynn Coffelt"
wrote:

A good deal of modern boat electronics wiring is connected to terminal
blocks by sticking the end of the wire into a hole where a screw-down clamp
holds the wire in place. It always looked like a not too smart idea to me,
but they neglected to ask me when the equipment was being designed.
My question is: How do you experts treat the wire ends that go into the
terminal block holes?

Europeans frequently use these compression terminals (Phoenix,
Weidmuller and other make nice terminal block systems using them), and
use ferrules (sp?) on the wires - metal sleeves, possibly with a
plastic part to go over the wire insulation - the ferrules are crimped
on the wire, before inserting the wire in the terminal, and make a
very neat installation. The normal ferrules do make it difficult to
get two wires in a terminal, but there are ferrules designed
specifically to handle two wires (I've never used them myself.)

These ferrules and crimp tools are available from Digikey, Newark and
others.

These European terminal block systems make really nice assemblies -
much nicer than our usual barrier blocks. With the optional parts
that allow you to bridge terminals, you can make quite fancy
distribution systems. See
http://members.shaw.ca/peterbb/dinblock.html


As a European of the British variety I would never use
(European designed) DIN rails on a boat - or anywhere subject
to moisture. They are intended for power wiring in enclosed
locations ONLY. OK, if you enclose them in a waterproof box
but not otherwise.

I think I'm agreeing with Larry - Use crimped ring terminals
on screw connectors. At least, with these, if the screw does
loosen due to vibration, the wire doesn't become disconnected
and go walkabouts. As an alternative, I'll use screw
connectors with the wire crimped into a bootlace ferrule or,
preferably, one with a hook on the end so the wire won't come
out in the event of the screw vibrating loose. (similar to
this: http://tinyurl.com/32pmmu)

And, yes, keep the metalwork the same so you don't get
electrolytic corrosion.

Ring terminals, hooked blades, bootlace ferrule or spade connectors,
IMHO if the terminal comes a bit loose you have probably got a burn
out on the connector and wire end anyway!
If you are considering Din rail mount terminals then take a look at
WAGO spring loaded terminals, no screws to come loose at all!

--

Richard

Nb "Pound Eater" Parkend G+S
"Governments are like Nappies, they should be changed often."
(For the same reason)

Why would it burn out? Burn outs happen from high current. You don't get high
current from loose connection, you get low current.


"Electricky Dicky" wrote in message ...
Ring terminals, hooked blades, bootlace ferrule or spade connectors,
IMHO if the terminal comes a bit loose you have probably got a burn
out on the connector and wire end anyway!

Chuck Tribolet wrote:
Why would it burn out? Burn outs happen from high current. You don't get high
current from loose connection, you get low current.


"Electricky Dicky" wrote in message ...
Ring terminals, hooked blades, bootlace ferrule or spade connectors,
IMHO if the terminal comes a bit loose you have probably got a burn
out on the connector and wire end anyway!


Loose connection gives you high resistance, so ALL the voltage drop is
across your 'bad' connection. So even though the the current will
reduce because of the higher resistance, most of the power will be in
the joint.

So if the current falls to say 2 amps and 12 volts drop is at the
connection then using W=IV we will have 24W. This is more than my mini
soldering iron.

On Sun, 04 Mar 2007 10:12:13 GMT, Bozo wrote:

Chuck Tribolet wrote:
Why would it burn out? Burn outs happen from high current. You don't get high
current from loose connection, you get low current.


"Electricky Dicky" wrote in message ...
Ring terminals, hooked blades, bootlace ferrule or spade connectors,
IMHO if the terminal comes a bit loose you have probably got a burn
out on the connector and wire end anyway!


Loose connection gives you high resistance, so ALL the voltage drop is
across your 'bad' connection. So even though the the current will
reduce because of the higher resistance, most of the power will be in
the joint.

So if the current falls to say 2 amps and 12 volts drop is at the
connection then using W=IV we will have 24W. This is more than my mini
soldering iron.

And JohnW wrote
Arcing/sparking or otherwise generating heat due to a higher
than normal connection resistance.

Thank you gentlemen, you beat me to it.

On the subject of "tight screws" IMHO the European metric "relatively
fine thread" allows tighter terminals (of any sort) than the US
threads! Stand by for flack! ;-)

--

Richard

Nb "Pound Eater" Parkend G+S
"Governments are like Nappies, they should be changed often."
(For the same reason)

Electricky Dicky wrote in
:

On the subject of "tight screws" IMHO the European metric "relatively
fine thread" allows tighter terminals (of any sort) than the US
threads! Stand by for flack! ;-)



100% true....

We still haven't learned which standards are the best. Compare the US' new
HDTV picture to the new HDTV picture in Europe. Ours sucks in comparison.

Larry
--
If the damned government isn't going to enforce
immigration laws, can they at LEAST park an ICE
paddy wagon in front of WalMart so I can find
a parking place and make the checkout line SHORTER?!

Bozo wrote in
:

Chuck Tribolet wrote:
Why would it burn out? Burn outs happen from high current. You
don't get high current from loose connection, you get low current.


"Electricky Dicky" wrote in message
...
Ring terminals, hooked blades, bootlace ferrule or spade connectors,
IMHO if the terminal comes a bit loose you have probably got a burn
out on the connector and wire end anyway!


Loose connection gives you high resistance, so ALL the voltage drop is
across your 'bad' connection. So even though the the current will
reduce because of the higher resistance, most of the power will be in
the joint.


http://www.youtube.com/watch?v=1jPZL...elated&search=
Not necessarily.....(c;
Even the power company guys were impressed!

Larry
--
If the damned government isn't going to enforce
immigration laws, can they at LEAST park an ICE
paddy wagon in front of WalMart so I can find
a parking place and make the checkout line SHORTER?!

http://www.youtube.com/watch?v=1jPZL...elated&search=
Not necessarily.....(c;
Even the power company guys were impressed!

Larry

Heck, even I was impressed.
Old Chief Lynn

Lynn Coffelt wrote:
http://www.youtube.com/watch?v=1jPZL...elated&search=
Not necessarily.....(c;
Even the power company guys were impressed!

Larry

Heck, even I was impressed.
Old Chief Lynn


Hopefully this does not happen very often in a boat with 12VDC...
I wonder what my chart display would think of that!!!!

Daniel