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Dangerous electrics
Comments
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Id like to understand how a cartridge fuse is better than a Rewireable for "clearing faults".
How does changing from cartridge fuse to Rewireable "improve performance?"0 -
Cartridge fuses are filled with sand..Once the conductor breaks, there is an arc which is quickly cooled by the sand, leading to shut off of current on the next current zero. And then you throw the fuse away and start again with a clean one.Id like to understand how a cartridge fuse is better than a Rewireable for "clearing faults".
How does changing from cartridge fuse to Rewireable "improve performance?"
Rewireables have to dissipate arc energy into air - the arc remains hotter for longer and over a few uses, will deposit metal on the inside of the ceramic cavity, which to my mind makes them suspect.You might as well ask the Wizard of Oz to give you a big number as pay a Credit Referencing Agency for a so-called 'credit-score'0 -
3036 Rewirable fuses vs circuit breakers from a time/disconnection point of view.
It all comes down to how the fuses or circuit breakers operate under fault conditions, wether that be short circuit or overload conditions, breakers and fuses all have different characteristics.
Rewirable fuses are still compliant with the current regulations, unlike some circuit breakers.
A 3036 rewirable fuse normally blows quickly under short circuit fault conditions as the current from the fault is sufficient to blow the fuse, however fusewire requires a much higher current than its rating to blow under overload conditions, look at the time curve graph for rewirable fuses...
http://wiki.diyfaq.org.uk/index.php?title=Fuse
So for a 5a lighting circuit...
13A for 5 sec
18A for 1 sec
24A for 0.4 as required by current regs in most cases domestically) *5 times the rated current of the fuse
32A for 0.2 sec
45A for 0.1 sec
Now look at a type b 60898 circuit breaker...
http://wiki.diyfaq.org.uk/index.php?title=MCB
For a 6A breaker
30A to trip from 0.1 to 5 sec ( not as odd as it sounds )
So at 30A or above disconnection in 0.1 sec due to magnetic strip operating.
Small overcurrent allowed,6.65A without trip however above that the thermal contact will operate and trip instantly at 9A
So yes the breaker performs better but in some aspects only marginally so, it is however when an rcd or rcbo is added that the benefit is really seen as faults are more likely to be detected and disconnection time is now in milliseconds and milliamps not seconds and amps.
oh dear oh dear oh dear. Please stop advising people twaddle - or at the very least actually try to learn something about the subject first rather than quoting from some wiki entry using scanned pages from BS7671 out of context. Oh, and I bet the BSI are just thrilled at the copyright infringement on that, too.0 -
Cartridge fuses are filled with sand..Once the conductor breaks, there is an arc which is quickly cooled by the sand, leading to shut off of current on the next current zero. And then you throw the fuse away and start again with a clean one.
Rewireables have to dissipate arc energy into air - the arc remains hotter for longer and over a few uses, will deposit metal on the inside of the ceramic cavity, which to my mind makes them suspect.
Put 1000+ amps of fault current through them and there's not an awful lot left - even 80A fusewire leaves nothing but a big black scorch mark on the asbestos pad!0 -
The biggest fault that rewireables have is simply that you have to rewire them - not always convenient to mess about with a fiddly job in the dark!0
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The advantage of that is that by trial and error you can increase the fuse wire size until you find something which doesn't blow ......The biggest fault that rewireables have is simply that you have to rewire them - not always convenient to mess about with a fiddly job in the dark!You might as well ask the Wizard of Oz to give you a big number as pay a Credit Referencing Agency for a so-called 'credit-score'0 -
I am a big fan of cartridge fuses over rewireables and MCBs.Shall we pretend you didn't just say that?! :shocked:
Just read what I say in favour of rewireables as being open to the advantages of something different.You might as well ask the Wizard of Oz to give you a big number as pay a Credit Referencing Agency for a so-called 'credit-score'0 -
You have asked an electrician for a report and he has correctly in my opinion found fault with the main tails to the consumer unit (among other things you have stated that are not visible from your photos)
To replace the tails in 25mm which is the minimum now recommended is impossible with old wylex consumers as the terminals are barely large enough to accept them and even if you manage to get them in somehow you then have to replace the earth conductor with 16mm and that definitely wont fit in a wylex earth bar so the best way is to swop the consumer unit.
A full test would then be required on the entire installation and looking at the mess just in the mains cupboard(probably carried out by a diyer) the rest of the house will be a mess too.
I think if you can get someone who is a registered electrician to repair and certify that lot for 700 quid I would bite their hand off
P.S don't pay a penny until you get a certificate.0
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