How many 60W bulbs have you seen on a single 5A lighting circuit?

[ianniann]

Some years ago after a minor explosion due to a short-circuit, I discovered that the fuse-box contained half a dozen strands of 5A fuse-wire. Looking more closely, the downstairs lighting circuit was trying to support 20 individual lampholders with 60W bulbs, one with three 20W bulbs, and a 200W transformer for MR16s. I imagine they must all have been on at some point, blown the fuse, and some wise guy decided more than one strand of fuse wire was the solution.

Has anyone seen worse?

 

[stillp]

I once had a customer tell me that he wanted a 32A breaker instead of a 6A because "it'll give better protection because it'll protect against a 32A fault, the other will only protect against a 6A fault".

 

[securespark]

O....K....

I went to a house once. Complaint on the screen was "Lighting fuse keeps tripping."

Not surprised. Once I had turned off, IR'd the circuit, re-energised with a couple of the lights switched on, I went round counting the loads.

There was 2600W of lighting.

ian, your 6.35A load should have been tolerated, even with 1 strand of 5A 3036...

 

[JohnW2]

Some years ago after a minor explosion due to a short-circuit, I discovered that the fuse-box contained half a dozen strands of 5A fuse-wire. Looking more closely, the downstairs lighting circuit was trying to support 20 individual lampholders with 60W bulbs, one with three 20W bulbs, and a 200W transformer for MR16s. I imagine they must all have been on at some point, blown the fuse, and some wise guy decided more than one strand of fuse wire was the solution.

Interesting. Even if that transformer was drawing its fall '200W' that's only a total of about 6A, so I wouldn't really have expected even a single strand of 5A fuse wire to have blown.

Kind Regards, John

 

[ban-all-sheds]

ian, your 6.35A load should have been tolerated, even with 1 strand of 5A 3036...

Ian - I1 is 1.8In for a 3036, i.e. 9A indefinitely through a 5A fuse..

 

[Mikefromlondon]

Interesting. Even if that transformer was drawing its fall '200W' that's only a total of about 6A, so I wouldn't really have expected even a single strand of 5A fuse wire to have blown.

Kind Regards, John

Don't forget the surge current when inductive loads are first switched on can be 10 x greater. And filaments also display similar characteristic.

 

[JohnW2]

Don't forget the surge current when inductive loads are first switched on can be 10 x greater. And filaments also display similar characteristic.

That's all true. However, the only inductive load is the transformer and, even if the incandescent bulbs were all switched on simultaneously, the 'switch-on surge' is so brief that I wouldn't really have expected it to blow a 5A fuse (an MCB might conceivably be a different matter). However, who knows?!

Kind Regards, John

 

[ianniann]

I'm not psychic and I don't know who originally set it that way, I'm just guessing. Maybe another customer that thought more fuse wire gives more protection?

 

[333rocky333]

Sure it was not strands of flex, I once went to a job where the woman had cut the lead off her old broken hoover and used a few strands of that

 

[ianniann]

Sure it was not strands of flex, I once went to a job where the woman had cut the lead off her old broken hoover and used a few strands of that

That would make for a good bang, I'm sure!

 

[JohnW2]

Maybe another customer that thought more fuse wire gives more protection?

As you imply, it wouldn't be the first time

Kind Regards, John

 

[333rocky333]

That would make for a good bang, I'm sure!

She actually had to call out the fire brigade, after the real fuse blew she put the flex in, not having a clue why fuses blow and like many just crack in a new one.
Not sure what the fault was now but when she put it in, she said within seconds there was smoke upstairs coming through the carpet from the gaps in the floorboards,
We found the earth core burnt right throuigh the side of the whole length of the T and E,
The poor girl was in tears when we got there and the whole circuit had to be rewired.
Some of the insurance callouts were quite heartbreaking, they were often lone females with kids

 

[ban-all-sheds]

Ye cannae change the laws of physics, and electricity has no compassion.