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International plugs and sockets

Chris Pearson
As we leave the EU, with all its standardization, I am bound to wonder why plugs and sockets have not been subject to this process. It isn't even that we have our funny square pins and the rest have round ones. Type C (2 pin) is common, but earthed plugs are mostly type E or F. IEC site.


Oh well, too late now!
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    Alasdair Anderson:




    Simon Barker:


    And a BS1362 fuse can be very reluctant to blow when overloaded. 


    Any fuse will be very reluctant to blow when overloaded - fuses are not overload protection, they are short circuit protection. From a 13A fuse protection you should be able to draw 20A for a significant duration (BS 1362 possibly indefinitely but certainly >3 hours). Generally overload protection is to protect the equipment, short circuit protection is to protect the electrical installation - somewhat simplified and I am sure you can think of many caveats and exceptions but in principle, that sums it up.

    Alasdair


     




    The bit about overload protection being for equipment is not true.


    Regulation Group 433.1 permits fuses to be used for protection against overload current; further, the requirements discuss selection of cable current carrying capacity in relation to the rating (and type) of the overload current protective device. Miniature circuit breakers are little different when operating in the thermal region.


    In terms of the role of BS 1362 fuse vs the connected appliance, the fuse is to protect the appliance lead, and not the appliance.


    If we are talking about protection against thermal effects during overload, it's possible to size the cable so the overload current protective device always protects the cable. The adiabatic criterion is only valid for faults of short duration, and the non-adiabatic method can be used - although if you follow Regulation Group 433.1 in relation to Iz this is not necessary.


    Using the non-adiabatic approach (long duration faults), it's possible to demonstrate that a 13 A fuse will protect a 6 A flexible cable against fault current and overload current regardless of the length.

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  • 0

    Alasdair Anderson:




    Simon Barker:


    And a BS1362 fuse can be very reluctant to blow when overloaded. 


    Any fuse will be very reluctant to blow when overloaded - fuses are not overload protection, they are short circuit protection. From a 13A fuse protection you should be able to draw 20A for a significant duration (BS 1362 possibly indefinitely but certainly >3 hours). Generally overload protection is to protect the equipment, short circuit protection is to protect the electrical installation - somewhat simplified and I am sure you can think of many caveats and exceptions but in principle, that sums it up.

    Alasdair


     




    The bit about overload protection being for equipment is not true.


    Regulation Group 433.1 permits fuses to be used for protection against overload current; further, the requirements discuss selection of cable current carrying capacity in relation to the rating (and type) of the overload current protective device. Miniature circuit breakers are little different when operating in the thermal region.


    In terms of the role of BS 1362 fuse vs the connected appliance, the fuse is to protect the appliance lead, and not the appliance.


    If we are talking about protection against thermal effects during overload, it's possible to size the cable so the overload current protective device always protects the cable. The adiabatic criterion is only valid for faults of short duration, and the non-adiabatic method can be used - although if you follow Regulation Group 433.1 in relation to Iz this is not necessary.


    Using the non-adiabatic approach (long duration faults), it's possible to demonstrate that a 13 A fuse will protect a 6 A flexible cable against fault current and overload current regardless of the length.

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