OK, you didn't write the rules.
But you can quote the rule(s) which somebody else wrote, which say that fuses rated at <13A should not be used with cables rated at ≥ 13A. Will you please do so?
Help with vintage electrics
- Thread starter pellio
- Start date
But you can quote the rule(s) which somebody else wrote, which say that fuses rated at <13A should not be used with cables rated at ≥ 13A. Will you please do so?
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Perhaps your question would be better phrased -
"By that logic, UK plug fuses below 13A provide no benefit with 13A cables, and need never be used with them."
No one would say a 6mm² cable should not have an OPD less than 45A but does it need one?
The regulations aren't going to specifically prohibit things which are not unsafe but that still does not mean they are necessary.
100A fuse wire has a csa of 3.14mm² (π) so why would it need the protection of a 3A fuse, instead of 13A, for the current drawn by, say, one table lamp?
NO. Because I don't believe there is a rule that says that. The rule is that the fuse in a plug is to protect the cable, not the appliance. So therefore a 13 amp fuse can be used with cables rated at ≥ 13 amp. Obviously smaller ones could be used but it is not necessary.
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OK.
W
Which rule is that?
There may not be a "rule" or "regulation" but it is (sort of) obvious by logic and design.
That's why the OPDs are there - to prevent damage to the cable and fire.
That is how circuits are designed. Design current of load > next size up OPD > next size up cable.
Nobody would fit a 250mA fuse for a single table lamp.
The 13A fuse and 13A plug were introduced because of the 32A ring circuit without which the flex would have had to have been the equivalent of 6mm² because of BS3036 30A fuses.
Without them (13A devices) Britain would today presumably have the same 16A radials as Europe with 16A plugs without plug fuses.
Had metric cable decided to be, what?, 3mm² then, with the introduction of MCBs, the ring could simply have been done away with, with no alteration apart from disconnecting one piece of cable, and left Britain with 3mm² radials with 32A MCBs.
While it may be said that the 13A fuse, and 16A circuit OPDs, might protect the appliances (from what?), there can be no reason to fit lower rated fuses unless lower rated cable is used (433 aside).
That being said does any appliance actually require lower protection from the fixed installation?
There cannot be any, can there? Europe would not be able to use them if they did exist.
Those that do need lower protection have internal fusing, presumably (obviously?) because the fixed installation does not have to cater for it.
That's why the OPDs are there - to prevent damage to the cable and fire.
That is how circuits are designed. Design current of load > next size up OPD > next size up cable.
Nobody would fit a 250mA fuse for a single table lamp.
The 13A fuse and 13A plug were introduced because of the 32A ring circuit without which the flex would have had to have been the equivalent of 6mm² because of BS3036 30A fuses.
Without them (13A devices) Britain would today presumably have the same 16A radials as Europe with 16A plugs without plug fuses.
Had metric cable decided to be, what?, 3mm² then, with the introduction of MCBs, the ring could simply have been done away with, with no alteration apart from disconnecting one piece of cable, and left Britain with 3mm² radials with 32A MCBs.
While it may be said that the 13A fuse, and 16A circuit OPDs, might protect the appliances (from what?), there can be no reason to fit lower rated fuses unless lower rated cable is used (433 aside).
That being said does any appliance actually require lower protection from the fixed installation?
There cannot be any, can there? Europe would not be able to use them if they did exist.
Those that do need lower protection have internal fusing, presumably (obviously?) because the fixed installation does not have to cater for it.
Europe (the bits of it that are not our glorious island) has a greater rate of electrical accidents that the UK, in spite of the relatively common use of 3A MCBs.
Do you mean the 3A MCBs have no effect on accidents, or
There would be many more without them?
There would be many more without them?
Neither, I meant that they sometimes use 3A circuits dedicated to low power accessories, where we would use an FCU.
Oh. Ok. You appeared to be linking it to the accidents.
That would seem to be rather restrictive - or
do they use 3A cable?
That would seem to be rather restrictive - or
do they use 3A cable?
Well we had 15A ones before the ring madness started.
Does anyone know what was common sur le continent before the days of MCBs?
No idea, but I doubt it! I remembered a manufacturer's sales figures, and I've seen 3A MCBs in hotel rooms.
No, the accident statistics were just an idea that they accept greater risks than we do.
That's a perception.
Do you have any comparative data for electrocutions in the home per head of population in different European countries?
Do you have any comparative data for electrocutions in the home per head of population in different European countries?
Didn't they have screw in fuses with an ES base on them?
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