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The customer says bootlace ferrules are the wrong type and wants them changing to fork-type crimps, arguing that the screw-clamp applies even pressure on fork crimps and a better contact but not so when ferrules are used - if you can picture the bootlace-ferrule on one side of the screw- with its clamp being at an angle as there is nothing on the other side of the screw. However, the termination is tight and makes a good solid contact with the ferrule so I think this is perfectly acceptable.
While I wouldn't generally disagree with a customer, there are hundreds of terminals to change, they didn't specify fork-crimps at design stages and I don't interpret anywhere in BS 60204-1 or BS 60947-1 that ferrules are wrong in screw-clamps.
Any opinions much appreciated.
if it were a few terminations I wouldn't hesitate to change them just to ‘keep the customer happy’ but we’re talking 50% re-wire of a panel that they had many opportunities to change during various design reviews.
We normally only use ferrules on fine stranded wires.
I like the idea of a flat forked crimp lug. What likely current will the crimp be required to carry?
Will vibration or door opening be likely to cause a terminal failure with a ferrule type connection?
Wire Ferrules Explained: Why are Ferrules Used and How are Ferrules Crimped - YouTube
This sort of thing will not be in the standards, (I;d be surprised if it was in anything to be honest) but the makers of the switches and so forth that have those terminals ought to be able to advise on the largest diameter they can be loaded to on one side only.
It may be worth noting that with the very few remaining designs of telephone junction boxes that make use of screw terminals, they are all designed to work with both single sided and double sided wire under the heads - BT at least accept wires under one side only..
This sounds like a typical personal preference rather than a regulation issue, and if the specification states no preference, you should not have to change them at your expense.
On a positive note, at least you used a crimp of some form, as i am surprised at the amount of installations, where no ferrules or crimps have been used
The panels have been supplied to global blue chip clients across many industries without issue.
I would never snag this on a panel whether working for the equipment manufacturer or the buyer, unless it was in a specification document.
Unless it is written into the signed contract I would be telling the client to jog on.
I have yet also to see a screw clamp terminal on a device that the device manufacturers state as unsuitable for a single ferruled class 5 or 6 conductor.
If it’s a machine panel then 60204-1 will take precedence over 61439 anyway.
Designing and building to 60204 meets the LVD (EESR) anyway. Where as the 61439 series does not meet the requirements for the MD (SMSR).
When it comes to it effectively the two pieces of legislation are mutually exclusive. It’s a declaration to one or the other for final piece of machinery. Which obviously has to be the MD/SMSR, as the LVD/EESR do not cover machinery, but MD/SMSR, covers the requirements of the LVD/EESR anyway.
The only reason why you would have to change, apart from placating the customer is if the connected device OEM states that a single ferrule is not acceptable in their product.
There is nothing in standards that requires a fork in a screw clamp connection.
I did check the data sheet albeit in a panic after I was challenged! Thankfully it does say to use ‘stranded or single core’. The person who challenged me happens to work for a highly respected blue chip company so had me reeling a bit. My mind is now rest assured though....He can jog on!