Ring to radial

[AdieB]

Had a call out to a home where the RCD keeps tripping when lounge ,dinning and bed room sockets mcb is switched on. Fault traced to one of the legs from the consumer unit to 1st socket 0.2Meg ohm at best. cable size is 2.5mm T&E there are 10 double and 4 single sockets on the circuit. Reg 433.1 seems to indicate that providing the floor area is limited to 50 m2 (the area in question is 3/4 the floor area of a medium size house. it would be ok to drop out the damaged leg from the consumer unit and socket fuse down to 20Amp mcb and leave as is. Possible to rewire initial leg and reinstate ring but do I need too?

what do you think?

AdieB

PS dropped leg out of consumer unit marked cable with tape and description of fault. Disconnected from socket and put wago type terminals on he cores. Changed mcb to16A (close's that was on van.)

 

[Guest125]

As long as the user does not require more than 20 amps seems fine to me.

 

[Andy78]

Why are you not replacing the damaged cable ?

 

[7029 dave]

Yes replace the damaged cable, and keep the ring.

 

[Farmelectrics]

put it on a 20a breaker and give the customer a price for installing new cable do you no were or how cable is damaged

 

[telectrix]

just explain to the customer that he's limited as too the load on the radial. give him a price to replace the damaged cable, then let him decide, once he has the facts.

 

[AdieB]

Only things plugged in would be TV, Sky, answer machine ,and maybe clock radio. Customer needs work done straight away as visitors arriving . Due to other commitments can't get there until next week.
adieB

 

[Pete999]

Only things plugged in would be TV, Sky, answer machine ,and maybe clock radio. Customer needs work done straight away as visitors arriving . Due to other commitments can't get there until next week.
adieB

replace the duff leg, keep it as a RFC, 3 hours job done, simples

 

[AdieB]

I have always been a Ring circuit kind of Guy (Old school). I thought that the new school is for radial circuits, as most hosing now has central heating and the power consumption on the power side is less than 20 Amp.

AdieB

 

[Knobhead]

Possible to rewire initial leg and reinstate ring but do I need too?

what do you think?

What do I think?

Stop being idle and get on with replacing the faulty leg and reinstate the ring.

Had the fault been at a mid point I may have agreed with making it two radials. No way would I agree to making a single radial and down rating by 62%.

 

[Octopus]

I've got a customer who's house has 1 x radial for the upstairs and 1 x radial for the downstairs! (and yes if they use too many kitchen appliances it trips the MCB!)

 

[SPARTYKUS]

Yes it can be suprising how little it takes in the way of 'things plugged in' to trip a 16/20 Amperes Radial circuit.

 

[Guest125]

What do I think?

Stop being idle and get on with replacing the faulty leg and reinstate the ring.

Had the fault been at a mid point I may have agreed with making it two radials. No way would I agree to making a single radial and down rating by 62%.

A little unfair. There could be many reasons why the client does not want it re-wired. Decorations etc. if the loading is taken into account then surely everyone is a winner.

 

[Guest125]

Yes it can be suprising how little it takes in the way of 'things plugged in' to trip a 16/20 Amperes Radial circuit.

Only suprising if it does not take about 16/20 amps???!!!! :willy_nilly::willy_nilly:

 

[Knobhead]

I can’t understand why the OP asked the question. No one would seriously back up his cheapskate excuse for not doing the job properly.

 

[Guest125]

I can’t understand why the OP asked the question. No one would seriously back up his cheapskate excuse for not doing the job properly.

I would back him up. He is not asking for our opinion on whether or not to rewire the ring. We are not there. He is. Be nice or don't be at all. ;-)

 

[Octopus]

replace the duff leg, keep it as a RFC, 3 hours job done, simples

??? based on what???

 

[Guest125]

??? based on what???

Based on clipping T&E surface as the crow flies.

 

[VoltzElectrical]

Put it on a 20A MCB, and give the customer a price for installing a new cable.

Do you know where or how the cable is damaged?

:book:

 

[VoltzElectrical]

If the installation socket outlet power requirements are below the new lower OCPD then leave it as a radial, thus avoiding disrupting the building fabric and further costs.

If higher current demands are required at a later date, then the ring can be reinstated or a new circuit installed.

Just my opinion.

The options should be provided to the client along with costs and implications.

 

[Plonker 3]

So you have the option of reinstating the RFC or just disconnecting both ends of one leg.

Why not reinstate what is there leaving no cables loose in the back of a socket or DB. What happens when they decide to start plugging more appliances in, as believe me customers dont always tell the truth about what they have plugged in.

 

[somersetsparks]

Surely if it's just stated happening there could be a fairly easy to pinpoint problem?

 

[Leesparkykent]

So you have the option of reinstating the RFC or just disconnecting both ends of one leg.

Why not reinstate what is there leaving no cables loose in the back of a socket or DB. What happens when they decide to start plugging more appliances in, as believe me customers dont always tell the truth about what they have plugged in.

charge them again for changing it back to a ring ;-) haha

 

[Plonker 3]

One other thing OP have you done your cable calcs for volt drop and worked out if the Zs value will be compliant?

 

[TJ Anderson]

One other thing OP have you done your cable calcs for volt drop and worked out if the Zs value will be compliant?

Pah.... making a right meal of it. Would you really sit there doing cable calcs for this?? I wouldn't. He can go at least 2.40 Zs on B16 60898. Experience would tell you, fit MCB and derate to radial, Quick Zs, MW, Done.

 

[Knobhead]

One other thing OP have you done your cable calcs for volt drop and worked out if the Zs value will be compliant?

You've saved me asking.

But for a Electrical Trainee what does that matter, he’s got the cash in his pocket and ridden off in to the sunset.

 

[Plonker 3]

Pah.... making a right meal of it. Would you really sit there doing cable calcs for this?? I wouldn't. He can go at least 2.40 Zs on B16 60898. Experience would tell you, fit MCB and derate to radial, Quick Zs, MW, Done.

Well yes I would and I am pretty sure most others on here would do too.

Anyone that doesnt design every circuit they install is in my wyes just a chancer that thinks of nothing but lining their own pockets.

 

[TJ Anderson]

You've saved me asking. He’ll be bloody lucky if it’s compliant.

He'd be bloody unlucky if it wasn't compliant!! Lighting Zs on 1mm 6242 in a house is very rarely over 1.50 Zs, this is 2.5mm. Real world.

 

[TJ Anderson]

Well yes I would and I am pretty sure most others on here would do too.

Anyone that doesnt design every circuit they install is in my wyes just a chancer that thinks of nothing but lining their own pockets.

Charging unnecessary time is lining your pockets. Using your experience to save a customer money is not.

 

[Anthony S]

what do you think?

AdieB

I would cover myself and go for a full rewire

 

[Plonker 3]

Then what happens if the Zs and volt drop are not compliant?

Who pays then?

 

[VoltzElectrical]

Well yes I would and I am pretty sure most others on here would do too.

Anyone that doesnt design every circuit they install is in my wyes just a chancer that thinks of nothing but lining their own pockets.

Something wrong with your eyes :54illb?

 

[telectrix]

wye eye, as geordie would say

 

[VoltzElectrical]

Then what happens if the Zs and volt drop are not compliant?

Who pays then?

On a serious note though, you make a valid point, but chances are if VD and Zs are ok on the old ring, they'll be ok on a lower rated radial.

This is not an excuse not to check though.

Though. Just thought I'd throw in another though as two didn't seem samey enough, Lol.

And another lol in case Eng 54 is reading! lol.

 

[TJ Anderson]

Then what happens if the Zs and volt drop are not compliant?

Who pays then?

Even if Zs was a bit over for MCB, which it almost certainly won't be, I would have no problem in utilising the 30ma RCD to provide satisfactory earth fault disconnection in this instance. This is not designing new circuits, this is getting someone up and running when they have a problem.

 

[GMES]

Here you go Voltz, I thought you might like to use this for your Avatar.

 

[Plonker 3]

Even if Zs was a bit over for MCB, which it almost certainly won't be, I would have no problem in utilising the 30ma RCD to provide satisfactory earth fault disconnection in this instance. This is not designing new circuits, this is getting someone up and running when they have a problem.

Pure laziness. Besides what happens if the RCD fails?

Replace the faulty leg get it back to how it was before and get paid.

 

[Guest125]

Pah.... making a right meal of it. Would you really sit there doing cable calcs for this?? I wouldn't. He can go at least 2.40 Zs on B16 60898. Experience would tell you, fit MCB and derate to radial, Quick Zs, MW, Done.

oh my god. Exactly what I was going to say. Absolutely ridiculous. Some on here just look for holes and use that to flex their BYB muscles.

 

[Guest125]

Well yes I would and I am pretty sure most others on here would do too.

Anyone that doesnt design every circuit they install is in my wyes just a chancer that thinks of nothing but lining their own pockets.

Crap. You are obviously out of practice.

 

[Guest125]

Then what happens if the Zs and volt drop are not compliant?

Who pays then?

..........