Is the use of ferrule crimps compulsory? Someone told me today that it has been a recent update in the regulations. I find this hard to believe. Thanks in advance!
Is the use of ferrule crimps compulsory? Someone told me today that it has been a recent update in the regulations. I find this hard to believe. Thanks in advance!
No. Not compulsory but one method of complying with Regulation 526.9.1 and 526.9.2. Probaly the most common and easy to use, ferrules and the correct crimping tool for the job and not using the incorrect usual 3 colour tool for ring terminals and the like.
JP
Exactly as JP says.
Just as with all connecting products, just make sure the ferrules used are to an appropriate standard, such as the German standards DIN 4662-1 or DIN 4662-4, French standard NF C 63-023, or UL standard UL486-F, and are the right cross-sectional area or configuration for the conductors being terminated. There are some available out there (eg from some on-line marketplaces) that don't appear to have a declaration to any particular standard.
Ferrules are generally unsuitable for Class I (single solid) conductors. They can generally be used for Class 2, Class 5 and Class 6 conductors in screw and cage type terminals unless stated otherwise by the terminal manufacturer. Some screwless terminals might also permit ferrules for Class 5 and Class 6 conductors under conditions stated by the terminal manufacturer.
The thing about using the correct ferrule size and correct faceted tool is key - there have been examples of expensive equipment needing to be recalled because the crimps 'fell off' in use, when in reality they were incorrectly selected or installed
If you don't have the right tooling, then in that case bare stranded wire under a screw terminal is less likely to fail than incorrectly ferruled stranded wire under the same screw...
Equally correctly fitted ferrules can do wonders for taming the ' whisker problems' that occur otherwise when stranded wires have to be terminated in the field in poor light or with poor access.
Note that there are special ferrules for allowing wires to share a terminal while the single wire ones can be persuaded, it is not good practice as the insulation may not seat in the cone properly.
Equally BS 7671 has not changed - the professional judgement is as it always was yours to make, but it maybe that local house rules or insurance requirements have been updated somewhere and this is what your friend is referring to.
Mike
Note that there are special ferrules for allowing wires to share a terminal while the single wire ones can be persuaded, it is not good practice as the insulation may not seat in the cone properly.
Occasionally, the force placed on the insulation when two insulated conductors are used in a sleeved ferrule intended for one conductor can damage strands on Class 5 and Class 6 stranded cables.
Why would you not?
134.1.4 also applies.
I agree with the previous comments - done badly is probably worse than not at all, but that is no excuse at all.
Why would you not?
Depends on the particular terminal - some lever or cage clamp types seem to perform better when the strands are able to move to conform to the shape of the terminal.But certainly for me, if flex has to be terminated into a conventional screw tunnel terminal, it's a bootlace ferrule every time for me. For stiffer 7-strand stuff (e.g. L&N or 4mm²+ T&E) usually seem OK just twisted in screw terminals.
- Andy.
For stiffer 7-strand stuff (e.g. L&N or 4mm²+ T&E)
For Class 2 conductors , only the minimum number of strands is mandated by the standards ... if the number of strands exceeds the standard, another approach may be necessary?
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