Ask The Trades - Rewireable fuses

kamog GDPR opt-out	Rewireable fuses May 4^th, 2009, 11:22pm Do rewireable fuses have to be replaced under latest regs? I have old Wylex consumer unit, still in 'as new' condition. I am told one can get plug in rcds which take the place of the old fuse which would be so easy to do but is there anything I should be aware of in changing fuse to rcd?
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The_Trician

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Re: Rewireable fuses
Reply #1 - May 5^th, 2009, 12:16am

You can't get plug-in RCDs - you CAN get plug-in MCBs.

You could fit a RCD in a stand-alone enclosure and protect the whole consumer unit with that.
Another thing to look out for, is that fitting a RCD can highlight faults that were previously masked by the use of just fuses, especially if any DIY add-ons have been made anywhere in the house.
Having proudly fitted your new RCD, you might well find that it won't set, or reset because a rewirable fuse won't pick up an existing earth fault.

As far as the regs go, the set-up you describe won't pass the new regs, but if you leave it alone it would most likely have passed earlier regs.

Welcome to the money-spinning world of how to make money for the electrical equipment manufacturers by constantly changing the wring regulations.

You see, had the IET Wiring Regs Committee - of whom comprises members from the UK Electrical Equipment Manufacturers, left the wiring regs to sensible chaps instead of Euro-Bureaucrats and crooks, we'd all still be safe with BS3036 rewirable fuses, or we may even have had a sensible breather for a while and just added a requirement for MCBs, but then again the kit makers would have most likely gone bust by now.

Instead, it has now been decreed that 'It don't Pass unless it's got a RCD.
Never mind that we now have to trust people's lives with a piece of kit which is not 100% fail-safe, but hey - they gotta make money!

'Innovation & Constant Tinkering With The Regs' is their Mantra.

Rant over

TT

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kamog GDPR opt-out Total Thanks: 8 For This Post: 0	Re: Rewireable fuses Reply #2 - May 5^th, 2009, 6:20am Alas you'll think I am an idiot but I typed 'rcd' when I meant to put 'mcb' I do know the difference in function but initials sometimes confuse me. As it happens there already is a separate rcd serving the consumer unit I enquired about.
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Lectrician

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Re: Rewireable fuses
Reply #3 - May 5^th, 2009, 6:28am

Quote:

Alas you'll think I am an idiot but I typed 'rcd' when I meant to put 'mcb' I do know the difference in function but initials sometimes confuse me. As it happens there already is a separate rcd serving the consumer unit I enquired about.

What rating is this RCD?

The new 17th edition requires 30mA protection to the majority, if not all circuits in a residential application. Having a single RCD covering the entire board does not comply - you need to split the installation into two halfs so if an RCD does trip you do not loose all power.

The circuits should be split so that if an RCD fails, the lights in one area go out, but the sockets stay on, and vica-versa for the other half.

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Y3 GDPR opt-out Total Thanks: 109 For This Post: 0	Re: Rewireable fuses Reply #4 - May 5^th, 2009, 4:57pm Lectrician wrote on May 5^th, 2009, 6:28am: you need to split the installation into two halfs so if an RCD does trip you do not loose all power. Although, this still doesn't fully comply with the 17th edition regs. Though a board full of RCBO's will>>>>> Expensive!
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Y3

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Re: Rewireable fuses
Reply #5 - May 5^th, 2009, 5:15pm

The_Trician wrote on May 5^th, 2009, 12:16am:

You can't get plug-in RCDs - you CAN get plug-in MCBs.

You could fit a RCD in a stand-alone enclosure and protect the whole consumer unit with that.
Another thing to look out for, is that fitting a RCD can highlight faults that were previously masked by the use of just fuses, especially if any DIY add-ons have been made anywhere in the house.
Having proudly fitted your new RCD, you might well find that it won't set, or reset because a rewirable fuse won't pick up an existing earth fault.

As far as the regs go, the set-up you describe won't pass the new regs, but if you leave it alone it would most likely have passed earlier regs.

Welcome to the money-spinning world of how to make money for the electrical equipment manufacturers by constantly changing the wring regulations.

You see, had the IET Wiring Regs Committee - of whom comprises members from the UK Electrical Equipment Manufacturers, left the wiring regs to sensible chaps instead of Euro-Bureaucrats and crooks, we'd all still be safe with BS3036 rewirable fuses, or we may even have had a sensible breather for a while and just added a requirement for MCBs, but then again the kit makers would have most likely gone bust by now.

Instead, it has now been decreed that 'It don't Pass unless it's got a RCD.
Never mind that we now have to trust people's lives with a piece of kit which is not 100% fail-safe, but hey - they gotta make money!

'Innovation & Constant Tinkering With The Regs' is their Mantra.

Rant over

TT

I love it when you go on one, interesting that UK electrical equipment manufacturers are part of the IET, explains everything!

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Lectrician

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Re: Rewireable fuses
Reply #6 - May 5^th, 2009, 5:37pm

Quote:

Lectrician wrote on May 5^th, 2009, 6:28am:

you need to split the installation into two halfs so if an RCD does trip you do not loose all power.

Although, this still doesn't fully comply with the 17th edition regs. Though a board full of RCBO's will>>>>> Expensive!

Why not Carl? Them dual split loaders we are all using not up to scratch? Perhaps someone should let the manufacturers know!

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Y3 GDPR opt-out Total Thanks: 109 For This Post: 0	Re: Rewireable fuses Reply #7 - May 5^th, 2009, 8:30pm Like TT said, the manufacturers are on the board of the IET
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Rewireable fuses Reply #8 - May 5^th, 2009, 8:32pm Yes, but seriously, why do you think that the 17th edition dual splits do not comply?
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plugwash Administrator Offline I love YaBB 1G - SP1! Posts: 1383 Total Thanks: 0 For This Post: 0 Trade: Not Specified	Re: Rewireable fuses Reply #9 - May 5^th, 2009, 9:18pm The new RCD splits seem to me to be similar to the old split loaders. Everyone uses them but IMO they violate at least the spirit and possibly (depending on how you read it) the letter of the discrimination rules.
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Rewireable fuses Reply #10 - May 5^th, 2009, 9:23pm Discrimination is based on devices of the same kind......MCB's and MCB's, not MCB's and RCD's for example.
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Y3 GDPR opt-out Total Thanks: 109 For This Post: 0	Re: Rewireable fuses Reply #11 - May 5^th, 2009, 10:36pm Lectrician wrote on May 5^th, 2009, 8:32pm: Yes, but seriously, why do you think that the 17th edition dual splits do not comply? Regulation 314.1
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Lectrician

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Re: Rewireable fuses
Reply #12 - May 6^th, 2009, 6:28am

Don't turn into chubbs Carl - Regs are better as words, not numbers!

Is this the reg that goes on about splitting up circuits as required to avoid hazards and inconvenience?

If it is, then the 17th edition boards will satisfy this reg in the majority of houses. Some larger houses may need other consideration. For example, a larger house we did recently had two dual slit loaders.

The boards where developed to give us a way to conform to these regs, and the design agreed not just by manufacturers! If you install one of these boards correctly you comply.

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« Last Edit: May 6^th, 2009, 7:02am by Lectrician »

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ChubbyPhaseWire GDPR opt-out Total Thanks: 109 For This Post: 0	Re: Rewireable fuses Reply #13 - May 6^th, 2009, 10:16am Quote: Do rewireable fuses have to be replaced under latest regs? No Take a look at 533.1.1.2
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Y3

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Re: Rewireable fuses
Reply #14 - May 6^th, 2009, 9:35pm

Lectrician wrote on May 6^th, 2009, 6:28am:

Don't turn into chubbs Carl - Regs are better as words, not numbers!

Couldnt be bothered to type the whole lot out lec, sorry

Lectrician wrote on May 6^th, 2009, 6:28am:

Is this the reg that goes on about splitting up circuits as required to avoid hazards and inconvenience?

Yes

Lectrician wrote on May 6^th, 2009, 6:28am:

If it is, then the 17th edition boards will satisfy this reg in the majority of houses. Some larger houses may need other consideration. For example, a larger house we did recently had two dual slit loaders.

The boards where developed to give us a way to conform to these regs, and the design agreed not just by manufacturers! If you install one of these boards correctly you comply.

Upstairs sockets with downstairs lights etc... on one RCD, and opposite way around on another RCD would cause inconvenience when a fault occurs. If a fault on one circuit is causing the loss of another circuit then this is an inconvenience.

An all RCBO installation would fully comply, dual RCD split loads are only partially compliant, not fully.

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Rewireable fuses Reply #15 - May 6^th, 2009, 9:51pm A single circuit tripping is also an inconvenience. At the end of the day these boards where designed to comply with the regs, and will fly through an inspection if done correctly. A board full of RCBO's is excellent, but not going to happen in the majority of cases.
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Y3 GDPR opt-out Total Thanks: 109 For This Post: 0	Re: Rewireable fuses Reply #16 - May 6^th, 2009, 10:56pm Lectrician wrote on May 6^th, 2009, 9:51pm: A single circuit tripping is also an inconvenience. To itself, not other circuits. The regulation doesnt mention a circuit causing an inconvenience to itself, but it does, to other circuits. All im saying is, they are not fully compliant, according to the reg
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