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Recommended checks before CU change

Former Community Member
Former Community Member
As most of you know I’ve only been qualified for just over a year and I’ve got a quote to do for a cu upgrade.


I know I’m nowhere experienced enough to do EICR’s yet, but what would you guys recommend I check/test before doing the cu upgrade and should I do these checks/tests at the quote stage?
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    sparkiemike:




    Fitzy71:

    Can anyone tell me what type of MCB's these are and if there's anything to look out for or be wary of when doing my inspection & testing?




    Wylex Push in MCB BS3871


     




    Yes, the push button type of Wylex M.C.B.s are indeed B.S. 3871 made to Stotz licence in England. The 5 Amp type is rated at 240 Volts with a breaking capacity of M1 (1kA). It has a white button indicator.


    Its more modern version with a toggle switch is again a B.S. 3871 Part 1 Type 2. Calibrated at 40 degree C. The 30 Amp version has a breaking capacity of M3 (3kA). Made in the U.K. This one has a red toggle switch.


    If the customers have used old fashioned tungsten filament lamps it is quite normal for them to trip a 5 or 6 Amp rated M.C.B  if they "blow", as the coiled coil filament springs about inside the glass bulb and "shorts" causing a high current to flow which trips the breaker very rapidly. This can happen with modern M.C.B.s as well on lighting circuits. It is not dangerous, just inconvenient.


    Z.




     

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  • 0

    sparkiemike:




    Fitzy71:

    Can anyone tell me what type of MCB's these are and if there's anything to look out for or be wary of when doing my inspection & testing?




    Wylex Push in MCB BS3871


     




    Yes, the push button type of Wylex M.C.B.s are indeed B.S. 3871 made to Stotz licence in England. The 5 Amp type is rated at 240 Volts with a breaking capacity of M1 (1kA). It has a white button indicator.


    Its more modern version with a toggle switch is again a B.S. 3871 Part 1 Type 2. Calibrated at 40 degree C. The 30 Amp version has a breaking capacity of M3 (3kA). Made in the U.K. This one has a red toggle switch.


    If the customers have used old fashioned tungsten filament lamps it is quite normal for them to trip a 5 or 6 Amp rated M.C.B  if they "blow", as the coiled coil filament springs about inside the glass bulb and "shorts" causing a high current to flow which trips the breaker very rapidly. This can happen with modern M.C.B.s as well on lighting circuits. It is not dangerous, just inconvenient.


    Z.




     

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