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garyt

garyt

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Hi still hearing conflicting information regarding good practice when terminating conductors in general, do most electricians still double over conducors although it can damage the copper connections.
Thanks.
 
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telectrix

telectrix

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i usually double if only 1 conductor in the terminal . if more than 1, then i don't.
 
gazdkw82

gazdkw82

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I double over if it's obvious the conductor will be small in a terminal....I.e, a single 2.5 in a socket, a small 0.75 flex into a spur etc...

I always aim to get the best possible connection between the terminal and the conductor itself.
 
telectrix

telectrix

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I double over if it's obvious the conductor will be small in a terminal....I.e, a single 2.5 in a socket, a small 0.75 flex into a spur etc...

I always aim to get the best possible connection between the terminal and the conductor itself.
flex in a FCU should be ferrules. go stand in the naughty corner. :p
 
littlespark

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I always make sure the terminal screw closes down on 2 surfaces, spreading the force. Either bending over a single solid core, or 2 unbent.
Fill up the terminal hole as much as possible.
 
David Prosser

David Prosser

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Aren't the terminal holes designed for one core then? It would be interesting to get an electrical accessory manufacturers input into this. It's more than reasonable to expect most common accessories to have either just one core in each connection or multiple cores in each one. Surly they should be designed to be equally secure with either option.
 
garyt

garyt

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  • Thread Starter Thread Starter
  • #8
i usually double if only 1 conductor in the terminal . if more than 1, then i don't.
Yes i think thats a good guide that i have always followed, but with the use now of the torque screw drivers i wonder if that will change.
 
Lucien Nunes

Lucien Nunes

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flex in a FCU should be ferrules
Unless the terminals are designed to accept fine-stranded conductors. The old MK FCUs with wrap-around screws with captive washers, for example, were specifically designed for flex and could not be used with ferrules.

In general I double solid and class 2 stranded conductors in pillar terminals that do not have a conductor protection tongue. The screw tip bites into the conductor ensuring a gas-tight contact even when the clamping force is spread over the greater number of contact points of the doubled conductor, and especially with solid conductors the elasticity is improved to resist thermal cycling. Without doubling, the screw tip sometimes deforms and weakens the conductor too much, or the force is badly off-centre if a solid conductor is trapped to one side of it, causing it to slacken after a small amount of cold flow.

If there is a protection spring I tend to leave conductors single unless the screw is likely to bottom out due to a mismatch in size. These terminals do not chew into the conductor so badly and the pressure is more even over the surface. Rising clamp terminals do not normally need doubling either, unless they are of poor design or construction with a tendency for the clamp to tilt over, in which case I would double and position the conductor to apply the force symmetrically either side of the screw.

Making a good connection is a craft in itself that used to be taught in detail. Some of it is common sense, but there are all sorts of specifics that can help achieve a good result with any combination of cable and terminal. Knowledge of the properties of different metals, thermal cycling effects, chemistry of corrosion processes etc. can make a difference when the conditions are more demanding.
 
Pete999

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I always make sure the terminal screw closes down on 2 surfaces, spreading the force. Either bending over a single solid core, or 2 unbent.
Fill up the terminal hole as much as possible.
There were occasions during my Apprentice days in the 1950s early 60s when I was taught to bind larger conductors with a core of the said conductor when connecting say as an example a 7/064 into a terminal designed to take a larger conductor, just thought you would like to know that piece of useless sorry useful information, to add to your knowledge data base, never know when something like that will save the day, do you?:p:p
 
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Dustydazzler

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I always fold over a single cable , it was how I was first shown

but I have worked with loads of newer day sparks who don’t bother folding over cores
 
Matthewd29

Matthewd29

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I double over all terminations up to 2.5mm where only one conductor is in the terminal.
 
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