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4mm2 twin and earth cable

Former Community Member
Former Community Member
regarding 4mm2 cable was it ever available in the old colours with solid conductors rather than the 7 strands version? Ive just done a pre - inspection of a property before doing an EICR and found 2 radial circuits fed from 32A MCBS. The cables appear to be  larger than 2,5mm2 . I'm going back to inspect this property with a view to reducing the MCB's to 20A if if they are 2.5mm2. I'm also taking  a Vernier  gauge to measure the cable diameters and compare to reference tables.

The installation is approximately 30 years old but is in very good condition.
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    Ebee

    The spring clutch on the thimble is there to give repeatable "feel" the big grey diameter on the picture above, the little knob is direct drive to make big movements quicker. An 1/1000 resolution micrometer (mechanical) is unlikely to be more accurate than 1 thou, probably less, that digital one measures inches to 1/100,000 of an inch, accuracy still +_ 2 or 3 microns, about 1 10,000th of an inch. You can see why a vernier is less accurate, the "feel" is just controlled by the thumb, not awfully repeatable.
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  • 0
    Ebee

    The spring clutch on the thimble is there to give repeatable "feel" the big grey diameter on the picture above, the little knob is direct drive to make big movements quicker. An 1/1000 resolution micrometer (mechanical) is unlikely to be more accurate than 1 thou, probably less, that digital one measures inches to 1/100,000 of an inch, accuracy still +_ 2 or 3 microns, about 1 10,000th of an inch. You can see why a vernier is less accurate, the "feel" is just controlled by the thumb, not awfully repeatable.
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