OT: house fires - electrical fault

Yebbut at least we got carpets on real floors.

Hasn?t done that in more than 40 years thanks, and isnt going to either.

With a ring main with a 36A fuse, possibly. But that is so rare that it makes no sense to be mandating that all plugs must have an internal fuse when that makes them MUCH less reliable.

And that is what the entire rest of the world has decided.

And now with far fewer rugs used, it just isnt a problem anymore.

How odd that no one else needed to do that.

The entire rest of the world knows otherwise.

Fuck all of them happen like that anymore in places where there is no fuse in the plug top.

Fuck all are that stupid even in Britain.

The yanks build timer frame & drywall in tornado alley - it hardly makes much difference whether it burns down or blows away in a storm.

And f*ck all else of the world is that stupid.

We don't have any more houses burn down that you lot do.

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** A short from active to neutral always produces a lot of current - 200A o r more and is normally only limited by installed cable resistance. This wil l trip any breaker or blow the supply fuse instantly.

But if the short is from active to safety earth, then current flow depends on the resistance of the ground connection. Here, we link the ground and ne utral conductors at the fuse panel so there is really no difference in the short circuit current in both cases.

But if the safety ground connection goes only to some local earth stake or plumbing, then the resistance may be much higher than the cable used - redu cing the fault current to a level that fails to blow a supply fuse. I under stand that this method was commonly the case in the UK in the past ( pre 19

60) and may still used be in some installations.

If you add the use of a ring mains with 32A nominal capacity and double tha t in overload condition - then it cannot be considered safe without every p lug containing a fuse capable of protecting the attached cable from catchin g fire.

As you mentioned, the use of an ELCB does the job much better since it dete cts any active-neutral imbalance and trips instantly.

.... Phil

UK mains distribution is by an armoured cable which effectively takes the form of co-ax. Live and neutral enter the property as one and the same, there are often earth staps added to any copper plumbing just to make sure.

Shorting live to either E or N will blow the plugtop fuse and trip the ELCB. The problem with cables hidden under carpet is the insulation gets crushed when people keep walking on it. Getting a proper short is getting lucky, all the dust and crap that falls through the carpet weave accumulates around hidden cables and provides the possibility of tracking/arcing between conductors with damaged insulation.

** But that was not the case in 1947 - which is the context here.

Rest of your dopey post snipped cos you changed the context.

..... Phil

Back then every town had its own power company and no such thing as standardisation.

Half the country had DC mains.

Its amazing that those old ways didn't drive us all back into caves.

Would this not be a potential problem with Single Wire Earth Return systems?

With that there is a resistance for both the Ground and the Nutural, both of which have to use the Earth as the return. If the Earth resistance becomes high enough, may it be unable to carry enough current to trip the fuse?

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Once upon a time, all water pipes were metal (often lead or iron back then) Nowadays most water pipes are plastic and completely useless for earthing.

Gas pipes were usually the same, and sometimes got used for the same purpose - but there were enough disasters to provoke legislation.

** Not normally.

** Not true.

The single conducting wire is not carrying 240VAC, but more like 10 to 20kV.

Each user has a hefty isolation transformer that passes only a small current to ground while providing 240VAC at high current to the user.

The user's earth and neutral conductors are linked and grounded as usual to a stake near the transformer.

.... Phil

Even more pig ignorant than you usually manage.

Even sillier than you usually manage.