Ring or radial please?

[Retired]

Hi,

Our detached bungalow with two room extension still retains just a single ring circuit for power and another for lighting; All the cable is in excellent condition it dating from 1964 when the bungalow was built. The power ring is in 2.5mm T&E and its this I'm concentrating on.

I'm going to give our kitchen its own dedicated circuit but would like information/advice please as to best circuit to use whether this be ring on 2.5mm T&E or radial on 4mm T&E? Which is favoured by you sparkys please?

I've been looking at loading in the kitchen and here is a list of items to be supplied by the new circuit;

Tumble drier.

Washing machine.

Fridge.

Toaster.

Vac

Fused spur to bathroom fan heater. 1.5mm T&E.

The floor area of both kitchen and bathroom is well under 50 square metres. I was going to go head with a ring circuit but I'm looking at options and have just been reading regulation 433.1 (Ring and final circuit arrangements).

I've already bought plenty WAGOBOX's and 221 connectors in readiness.

Kind regards, Colin.

 

[Andy™]

either would work. my preference is usually 32a ring for the kitchen and 20a radials for rest of house, although that can change depending on job

 

[Revved Up Sparky]

If you decide to go for 4mm T&E I would recommend 35mm deep boxes rather than 25mm. IMHO it makes it a little easier to fix the fronts on. 

I myself am in the process of rewiring my own house and -  like Andy, I am running radials for the 3 living rooms and 4 bedrooms (for the bedrooms containing my teenagers/ young adults the circuits are going via a DP switch by my bed ) plus I will put a ring main in for the kitchen. 

 

[Retired]

Hi,

Many thanks Andy and Revved Up Sparky for your replies which are most helpful.

I'm getting ready to install a new BG 16 way consumer unit and want to know the circuits are fine before removing the current consumer unit. Things have changed a bit in the 25 years since I installed this current CU. I've got the usual DMM's and have just bought a Kewtech Loopcheck 107 which reads good. I've also bought a Fluke Volt Stick and cable tracer plus a new headlight.

Thanks for the 35mm box tip Revved Up Sparky; I'll go with the ring circuit as you both suggest using 2.5mm T&E so the boxes already installed should be fine but as I'm working under the bungalow I'll use the WAGOBOX's and connectors as needed; I can take my time to do a top job but I'm researching first in order to meet regulations; only the two of us my wife Bron and I live in the bungalow so electrical demand won't have Sellafield on overtime but I want to do this job once and know it will meet any future demands. I'm competent with electrics but the regulations seem to change daily.

32A Ring main it is so question quickly answered; many thanks once again guys.

Kind regards, Colin.

 

[apprentice87]

You are going to need something for measuring continuity and insulation resistance too.

john..

 

[Evans Electric]

Ring main to kitchen in 2.5     4.00mm  is quite expensive in relation to its size because not much is sold compared to other sizes. 

You only need two joints really.  Find the two legs in & out of the kitchen ,  pull them out & connect them straight through then wire a new ring to kitchen .   Any switched spurs , use a 35mm  KO box . 

All appliances should have an accsessible means of local isolation , so no sockets hiding behind washing M/c  or freezer  , stick them in the cupboard next door.

 

[Evans Electric]

Hi,

Many thanks Andy and Revved Up Sparky for your replies which are most helpful.

I'm getting ready to install a new BG 16 way consumer unit and want to know the circuits are fine before removing the current consumer unit. Things have changed a bit in the 25 years since I installed this current CU. I've got the usual DMM's and have just bought a Kewtech Loopcheck 107 which reads good. I've also bought a Fluke Volt Stick and cable tracer plus a new headlight.

Thanks for the 35mm box tip Revved Up Sparky; I'll go with the ring circuit as you both suggest using 2.5mm T&E so the boxes already installed should be fine but as I'm working under the bungalow I'll use the WAGOBOX's and connectors as needed; I can take my time to do a top job but I'm researching first in order to meet regulations; only the two of us my wife Bron and I live in the bungalow so electrical demand won't have Sellafield on overtime but I want to do this job once and know it will meet any future demands. I'm competent with electrics but the regulations seem to change daily.

32A Ring main it is so question quickly answered; many thanks once again guys.

Kind regards, Colin.

Don't forget consumer units need to be metal now , Colin , and are recommended to be readily accessible due to resetting breakers , / RCDs etc  so they are not fitted up against the ceiling anymore .  Take the opportunity to re- fit it at a sensible height if possible . 

 

[Andy™]

Thanks for the 35mm box tip Revved Up Sparky; I'll go with the ring circuit as you both suggest using 2.5mm T&E so the boxes already installed should be fine but as I'm working under the bungalow I'll use the WAGOBOX's and connectors as needed

avoid connections as much as possible, especially those that wont be accessible. yes, they can be there, but if you can avoid it in the first place less to go wrong

as for box depth, might want to use 25mm on light switches rather than 16, much easier if you want to fit a dimmer switch or flat plate stuff

 

[Retired]

Hi,

Thanks apprentice87 for suggesting insulation & continuity checks; I have a 1,000V Evershed & Vignoles Megger which should prove insulation is OK and DMM on ohms for continuity or a small test lamp or possibly even the tone cable tracer? Wouldn't the Kewtech Loopcheck107 indicate a fault on a ring? 

Thanks Evans Electric for your excellent and informative advice. Yes I agree regarding breaking the existing ring circuit to isolate the kitchen and simply rejoin the ring for continuity allowing the kitchen then to be sorted with its own ring circuit; both washing machine and tumble drier are located side by side under a work surface with their supply via a double switched socket placed neatly in a base unit very nearby; same with the fridge so all three can be isolated quickly and easily whilst being away from accidental damage. A wall double switched socket is fed directly from the CU it being a single cable so I'll re-connect as a spur into the new ring circuit; I've just been measuring this stranded T&E to ensure its 2.5mm its seven strands at 0.75mm per strand; the outer sheave isn't marked. I'll check all connections under the bungalow and remove any junction boxes; its going to take time and effort but will be worth it for peace of mind; I've just removed a short cable which came out of the CU up into the ceiling and disappeared through a load bearing wall; I had the computer hooked up to this but I was surprised when I ran the cable tracer it powered nothing else; I've since added another double socket so the computer kit now is supplied via two switched double sockets on the ring main; exit another unwanted cable; I've used sig gens many times during my radio restorations but this new tone cable tracer really is the business for household cable tracing. I'm using 2.5mm T&E for the new ring and any spurs. Thanks also for the height information for the new CU. Yes its a fully compliant brand new 16 way metal clad British General CU and I'm using flat cable glands which I've already bought for the entries (Wiska) also I've pre wired for 25mm +16mm tails allowing double insulation right up to the connections whilst the CU is sitting on the bench; the correct Wiska gland is installed (TKE/P40); the tails are 2M long and I won't cut them until the CU is in position; the current tails are 16mm so I'm upgrading but will leave the 80A mains fuse installed; I've been known to measure five times and still cut timber too short? I've bought a stepped drill plus a number of hole saws because the entries at 20mm are too small they need opening to 25mm which again I'll do on the bench and whilst at it add extra glands for future expansion but seal the unused glands. The current CU plus the garage CU will be removed and I've made a new 18mm thick backing board with standoffs to mount the new items on this is stained and varnished with a Roman Ogee moulding to each edge picked out in black;  I'm also installing a new mains to CU isolator it being a Wylex 100A DP mains switch. I've also bought blue and brown PVC sleeving; might as well have correct colours whilst I'm at it. The garage ceiling is very low at only 7' and as I have lots of machinery and keep moving things around the new CU will be located near the ceiling as a direct replacement allowing easy access but keeping it away from accidental damage; I'm not sure if I can attach a picture of before and after. I don't care how much I spend or how long it takes to do the work; I want to go over the top and look at every little detail in fact I'm enjoying myself without feeling under any pressure.

Thanks Andy; your reply popped up just as I was going to hit submit. I can leave the lighting circuit alone as its suitable for our needs but I do want to sort out the ring main and old CU which is what I'm now tackling; I agree in using as few connections as possible but again I've been looking at my options and having seen Wago mentioned looked into this because Wago is totally new to me; I've now bought WAGOBOXES and 221 connectors as these seem favoured to junction boxes; I've never liked struggling with junction boxes in inaccessible places hoping all the screws were fully tightened; I hope Wago gets the thumbs up; I also bought Wiska grommet type entries where the cable is pushed through but I'm not keen because they appear quite flimsy so I've now bought Wiska flat cable glands; I like proper glands for security.

When I started this I thought its going to be a simple CU replacement until I started to think about upgrading; I'll have to stop thinking because it causes me lots of extra work. As long as I'm pottering around keeping busy I'm happy.

Thanks guys for your welcome replies; pity Scoobs are limited.

Kind regards, Colin.

 

[Andy™]

DMM is not suitable for testing continuity. regs require a 200ma test current

 

[Retired]

Hi,

Thanks Andy for the information; I'm learning all the time; I'll have a look at this testing once it's all installed.

Kind regards, Colin.

 

[apprentice87]

As Andy said above... Not sure if an ordinary DMM will be accurate enough at the low resistances involved... The megger will be fine though!!

What you all think about Zs though??? If you tested continuity when verifying the ring with a test lamp, [which i suppose you could] how you going to check Zs?? I know you could try to calculate it from Ze and the cable length, but it would not be much fun.. and very prone to error i would think..

john..

 

[apprentice87]

Hi,

Thanks Andy for the information; I'm learning all the time; I'll have a look at this testing once it's all installed.

Kind regards, Colin.

There are tests you need to do when in the process of installing it, that is the problem.. "Google initial verification of ring circuit"

john..

 

[Murdoch]

I've already bought plenty WAGOBOX's and 221 connectors in readiness.

what for?

 

[Retired]

Hi,

Many thanks John; thanks for the nod I'll have a look.

Thanks for asking Murdoch; I bought the Wago items after reading about the dangers of junction boxes in confined spaces such as under floor boards where they aren't accessible for testing and screws coming loose resulting in fire risk; as I've stated Wago is new to me and for a few quid I'm happy to try them out; it was members on this forum who brought my attention to Wago so I'm still learning; the Wago videos look good but I wonder what these are like in the real world? Are junction boxes under floor boards now outlawed under 17th Edition wiring regulations; I've already found a couple of junction boxes and its no problem to change them whilst I have access; sorry if I seem thick but I've been doing lots of web browsing and reading; as they say a little learning is a dangerous thing. There's nothing to stop me getting a sparky in to test once the job is completed; I installed our current CU over 25 years ago doing the job live (NOT RECOMMENDED)  without difficulty and it's never had any problems; it tests good with my new Kewtech loopcheck107  socket tester. I admit I'm not a sparky but I'm not a novice either. 

Kind regards, Colin.

 

[Murdoch]

My preferred JB for such situations are the Hager J803 and J804....

If installed corrected old JB's can last for years....... unlike lots of the cheap carp we buy these days.

 

[Andy™]

Hi,

Thanks Andy for the information; I'm learning all the time; I'll have a look at this testing once it's all installed.

Kind regards, Colin.

i would suggest getting a copy of the on site guide, plenty useful info in there

you also do you cable calcs to determine cable size etc before you wire anything, then testing should give you the same results as your design. but tbf, in a house its a bit simpler

 

[Evans Electric]

Your existing socket cables are pre-metric size 7/.029   by what you said  so they're OK  .

The point of the Wago connectors is they are deemed to be maintenance free with no screws .  A recent reg. change announced we could hide them forever if required .    

Just a point on continuity of ring main ....if you install it  you will know whether its a complete ring or not , that old Megger you mentioned will prove it .   Surely you're not going to buy test instruments for a DIY job .

Because you say its a bungalow I'd say  If you sat down & did all the cable calc stuff  you would still be using 2.5mm so don't worry too much about that ...just crack on  with it .  

(Might worry if your bungalow was 50 mtrs long  . ) 

I can assure you that your original install in the bungalow was never tested  in the 1960s and a five page document issued .

Take your time & enjoy doing it . 

 

[Retired]

Hi,

Thanks Murdoch for your Hager JB information. I've just been browsing the web for installation details on these Hager JB's and also on YouTube but its taking quite a bit of time so I'll have another look tonight; I did find details on YouTube about Debox SL with FREE Screwless Terminal Block; as I say though I'm learning all the time and its interesting to see what is now available; the Hager has cable clamp screws and "fits nicely in the hand" ? I like the look of the Hager JB's though they look a nice bit of kit. I bought ten WAGOBOXES and plenty of WAGO 221 connectors so I'll see how I get along with these; this forum though is brilliant as you experts know about all the up to date materials and methods whilst being generous and most helpful with your information and suggestions. 

Thanks Andy; I think I'm pretty safe using 2.5mm T&E for power rings and 1.5mm T&E for lighting; I'll check the cooker cable to ensure its all in at least 6mm T&E. I could spend a great deal of time just reading rather than getting on with the job but I'm keen to do both as I want to be absolutely sure everything is safe and complies with regulations.

Thanks Evans Electric; I did wonder what the older cable was so its nice to know its 7/.029; I'll double check to be safe though. I've spent many hours browsing the web for up to date information and this is how I ended up choosing Wago products because some of the JB's will not be easily accessible once installed. No I'll not spend a lot of money on test instruments just for this one off job; I'm pretty sure the equipment I already have is sufficient considering when 25 years ago when I installed our current CU I hadn't a clue what a DMM was and I think 25 years trouble free service indicates nothing too much wrong; my new Kewtech Loopcheck 107 also reads "Good". I've never used my Megger though on household wiring so it's going to be new to me hooking up to the three ring mains; garage; main bungalow and kitchen.My first thoughts are to obviously isolate the power then for simplicity of connecting the Megger use a 13A plug but leave the cap off and hook the Megger onto the terminals then crank up? I'll unplug and isolate anything from the circuits because 1,000V injected will be searching.

I fully appreciate the need for safety when it comes to electricity regarding shock and fire risk but how far is this safety going to go; I'm only speaking from work I do myself so its not a case of someone on a new housing estate is going to cut through a cable or bang a nail through a cable; I'm working entirely on my own and I've managed to repair much more complex electrical kit like vintage radio/TV without introducing shorts or faults of any kind; I can't help thinking all this testing is fire fighting rather than having the skill to to the job correctly in the first place? I'm not trying to provoke discussion on this subject of testing but I've been in industry for a lifetime and I see the difference between those who are idiots and those who are genuinely skilled; are we heading to installing a single conductor between two terminals then having to fully test that all is well in case we've been careless and nicked the insulation or failed to nip up a screw? Years ago Bron and I were watching a TV program where apprentice electricians were let loose on a new build; we were appalled by what we saw; bare conductors and two nails through a cable and the two apprentices thought it was funny; had I done anything like this in the pit I would have been beaten up by the engineers who made absolutely certain all my work was up to scratch. Once final testing is carried out then everything is perfect until the new home owner does something silly; however safe something is made it will never be idiot proof.

At almost 70 years of age I've been around the block a few times and looking back over this thread I'd like to stress I'm not encouraging novices to play around with electricity which would be highly reckless of me; neither am I criticizing testing but this electrical testing is becoming increasingly complex involving expensive test instruments and endless ever changing regulations; how many tests does it take before a circuit is considered safe? On our current CU if a light bulb blows it knocks out the lighting circuit; this is an improvement over the original wired fuse boxes I replaced but now I'm upgrading once again to a split load CU with a pair of RCD's.

Below are pictures of our current Wylex 6 way CU; our new BG 16 way CU with mains tails pre-installed and a project I did years ago installing my own 3 phase 415V into the garage; the method I used for winding on the coils is entirely my own idea it being a long wooden shuttle which I could thread through the lamination's making for a very neat winding; I bought 3 x instructional DVD's from Unique3phase in America and although I've not received any electrical training I successfully installed 3 phase costing just under £120 at the time; Douglas Arndt the creator of Unique3phase now kindly credits me with the shuttle winding method. 240V in 415V out  (third phase 600V to compensate for capacitor drop) and once my machines were phase balanced to this transformer they ran at full power and I could run a single or multiple machines up to the transformer output limit; the transformer weighs around 75kg anyway I've just added this because I think I'm competent to work on our household electrics but I'm in no way complacent hence I do a lot of research up front and is why I added this thread. I'm not a casual DIY'er having just designed and built a 4 HP saw bench which is the reason I'm upgrading the electrics and CU. Many thanks moderators for not jumping on me; I tend to ramble on and go off topic but hopefully its interesting and in a way all this is related.

I think its stopped raining so time to get something done.

Kind regards, Col. 

 

[Murdoch]

^^ I still don't understand why you think you need so many wago boxes and parts. It's practice these days too have all connections at sockets, switches and lights only