Ring final circuit vs Radial final circuit

[LukeScotty]

lawsonium, lenny theloon is intitled to his opinion, Im not saying he is right or wrong, but does share a valid point

 

[lawsonium]

Thanks for your replies...

Do you intend to notify local building control before you do any electrical work on your house???

Is it really necessary to notify them when you are simply wiring in a couple of lights in an outhouse? Surely the proliferation of kits for outside security lights etc etc in popular DIY stores flies in the face of this idea?

As for spurring off an existing storage heater circuit - definitely not!!!! those heaters use a lot of power which is why it's one circuit per heater.

Well, the property I have is ex local authority and subsequently has been wired and re-wired by the local authority.
There are three separate economy7 circuits in the house, two of them are just a single heater per circuit but the third has (or should I say had) two large storage heaters on it.
I have removed both heaters as they were either side of a wall I needed to put a doorway through. I now have a single circuit with nothing on it (i.e. not spurring off another appliance).

My question was/is, does anyone here think it is a good idea to run this, now unused economy7 circuit, to the outhouse laundry to run the washing machine/drier after 12 midnight?
Also, can you purchase some kind of automatic switch to switch over to economy7 on a timer basis for a fridge freezer?

Kindest Regards,

Matt.

 

[Guest123]

Thanks for your replies...



Is it really necessary to notify them when you are simply wiring in a couple of lights in an outhouse? Surely the proliferation of kits for outside security lights etc etc in popular DIY stores flies in the face of this idea?


quote]

Hey Matt.

Probably without knowing it you have hit upon the biggest problem with the whole part P thing since it began.

What you have said is absolutely bang on, how can anyone take part P seriously when all the DIY stores continue to sell electrical equipment to anyone but technically, depending on what your doing and where your doing it it's against the law!!!!!

I'm sure if you look through the forum you will find numerous threads on this very topic.

Anyhow if the circuit is unused I dont see a problem with extending it providing that you make sure the earthing is upto standard and all disconnection times are still met. Bear in mind that the circuit will only be "live" between 12 + 7am so it wouldn't really be practical for a fridge.

Also you would need to check the loading of the washing machine and the drier if they are to be used at the same time, to make sure you dont exceed the current carrying capacity of the cable used in that circuit.

Cheers.

 

[mrloy99]

Thanks for your replies...



Is it really necessary to notify them when you are simply wiring in a couple of lights in an outhouse? Surely the proliferation of kits for outside security lights etc etc in popular DIY stores flies in the face of this idea?




Well, the property I have is ex local authority and subsequently has been wired and re-wired by the local authority.
There are three separate economy7 circuits in the house, two of them are just a single heater per circuit but the third has (or should I say had) two large storage heaters on it.
I have removed both heaters as they were either side of a wall I needed to put a doorway through. I now have a single circuit with nothing on it (i.e. not spurring off another appliance).

My question was/is, does anyone here think it is a good idea to run this, now unused economy7 circuit, to the outhouse laundry to run the washing machine/drier after 12 midnight?
Also, can you purchase some kind of automatic switch to switch over to economy7 on a timer basis for a fridge freezer?

Kindest Regards,

Matt.

I don't know how technical you are but your fridgefreezer changeover could be performed with a simple relay,suitably rated and installed beside your consumer unit,if you have a dedicated circuit.

 

[lawsonium]

Hey Matt.

Probably without knowing it you have hit upon the biggest problem with the whole part P thing since it began.

What you have said is absolutely bang on, how can anyone take part P seriously when all the DIY stores continue to sell electrical equipment to anyone but technically, depending on what your doing and where your doing it it's against the law!!!!!

Hi Lenny, thanks for the input. I have to say I tend to get infuriated by all the red tape in the world. Over complicates things. Virtually everything is against the law these days or offends someone.

Anyhow if the circuit is unused I dont see a problem with extending it providing that you make sure the earthing is upto standard and all disconnection times are still met. Bear in mind that the circuit will only be "live" between 12 + 7am so it wouldn't really be practical for a fridge.

Also you would need to check the loading of the washing machine and the drier if they are to be used at the same time, to make sure you dont exceed the current carrying capacity of the cable used in that circuit.

I haven't calculated it yet but I can't see that a washing machine and a drier are going to out load two big storage heaters. I will check the values and cable ratings before I install though, thanks for the warning.

As for the fridge/freezer, I am hoping to implement some kind of relay as per mrloy99 has suggested to automatically switch the power over at the point of changeover.
I don't know exactly how this is to be acheived but I can imagine it is readily available.

I don't know how technical you are but your fridgefreezer changeover could be performed with a simple relay,suitably rated and installed beside your consumer unit,if you have a dedicated circuit.

Hi mrloy99, thanks for your reply. I am keen to know more about this relaying idea. I assumed there would be a device available for this very application as I can imagine it would be commonly required.
Is it better to run an E7 circuit AND a normal circuit to the laundry and have a switch/relay near the utilities or as you have said near the CU, which I am guessing would require using the same cabling to the laundry for both types of supply?

Kindest Regards,

Matt.

 

[mrloy99]

Hi Matt,Reference your changeover relay,I don't know of a device specifically for this application as such but this might be something you could get an electrician to do for you but basicly if you connect this at the consumer unit you won't have to install another circuit.Your relay should be available at major electrical wholesalers(suppliers to the trade).
You would require an 8 pin plug in relay and base and a suitable mounting enclosure with din rail.You have 2 normally closed contacts and 2 normally open contacts and 2 commons and a coil contact(known as A1 andA2).The 2 sets of contacts would enable double pole switching.You mentioned previously that you have now a spare E7 circuit.Whenever you apply power to your coil say whenever the E7 comes on the relay would change over from normal tarrif to off peak and thence out to your circuit.The connections are straight foreward.Pm me if you need more detail.

 

[lawsonium]

You would require an 8 pin plug in relay and base and a suitable mounting enclosure with din rail.You have 2 normally closed contacts and 2 normally open contacts and 2 commons and a coil contact(known as A1 andA2).The 2 sets of contacts would enable double pole switching.You mentioned previously that you have now a spare E7 circuit.Whenever you apply power to your coil say whenever the E7 comes on the relay would change over from normal tarrif to off peak and thence out to your circuit.

Hi mrloy99, this sounds perfect, just what I require. I will ask some local sparks if they fancy the job perhaps. Thanks for the offer to PM as well.

As for my standard socket/light radial circuit, what do I need to think about when extending these?
For example, I have a circuit with JUST a twin socket point, what should I be looking for if I wanted to extend this by adding another twin socket?

From what I have read on this site, it is as straight forward as wiring another spur and taking note not to exceed the cable loading.

Kindest Regards,

Matt.

 

[mrloy99]

The circuit could most likely be extended useing 2.5mm cable to your additional socket,then if you wanted to supply your lighting also from this circuit,the normal practice would be to install a switched fused spur unit,also fed with 2.5 cable,and then come out of your switched/fused spur unit with 1.5mm cable to your lights,protecting your cables with conduit or mini trunking as required. Of course you should also take heed of the previous posters comments,regarding notification and testing etc.You should also ensure that any sockets are supplied via 30ma rcd.The same would apply for your other altered circuits.ie fit 30ma rcd
on E7 board also.

 

[lawsonium]

Of course you should also take heed of the previous posters comments, regarding notification and testing etc.You should also ensure that any sockets are supplied via 30ma rcd.The same would apply for your other altered circuits.ie fit 30ma rcd
on E7 board also.

Of course, I don't intend to ignore the sensible warnings. I will be getting all works checked by an electrician.

All sockets are on 30ma rcd's so I would only be extending from these. With regards the lights I doubt I will be adding to the lighting circuit but if I do I will probably extend the existing circuit rather than spurring off the sockets.

There is only one CU on the system currently and I am only assuming at this point (haven't checked yet) that the spare E7 circuit is being fed from rcd's installed in the CU. What are the rating likely to be for storage heaters? Surely they must be at least 30ma's?

Another thing is that the CU is now full and I'm wondering if I should be thinking about replacing it with a newer, bigger one or if I should be getting the local board to install an isolation switch and feed a second CU from a split tail?

Any thoughts?

Regards,

Matt

 

[mrloy99]

sorry,didn't realize you had existing lights out there.
Not sure what set up you have there,if you only have one c.u.
The ones I've seen before have twne for ordinary tarriff and another for off peak.Maybe the whole lot is on a dual tarriff supply.You might be getting in over your head here,but I will go on.As far as I know and am sure the learn'd brothers will correct me,but I believe that any new work has to comply to 17th edd.So if you extend your "E7" circuit to become a socket,all sockets need 30ma protection. However if you change the consumer unit,protection to 30ma will be required on all circuits in bathroom and all circuits with cables buried in a wall at a depth of less than 50mm,which in effect normally means all circuits.A dual rcd system is commonly employed,with the object being that you are not left without SOME power in the house.For instance it has become normal practice to install upstairs lights and downstairs sockets on one rcd and downstairs lights and upstairs sockets on another rcd.It would also require that your main earth bonds are checked and upgraded as necessary at this time.
All circuits should then be tested and readings noted on appropriate form for submission to council who will then charge you their fee to have work inspected...If you could include a photo of your c.u and meter it might help.

 

[brs73]

one of the tutors at college told us that one of the reasons for a ring was that if one leg of the earth was broken/disconnected ,then you'still have an earth from the other leg of the ring.

err, this post shouldn't be here. i was quick replying to another thread!!??

many,many,many moons ago,one of the tutors at college told us that one of the reasons for a ring was that if one leg of the earth was broken/disconnected ,then you'still have an earth from the other leg of the ring.

 

[mrloy99]

one of the tutors at college told us that one of the reasons for a ring was that if one leg of the earth was broken/disconnected ,then you'still have an earth from the other leg of the ring.

err, this post shouldn't be here. i was quick replying to another thread!!??

many,many,many moons ago,one of the tutors at college told us that one of the reasons for a ring was that if one leg of the earth was broken/disconnected ,then you'still have an earth from the other leg of the ring.

Yes,and same for a neutral or a live!!---everything would apparantly "work" but,if the cable, say live,was broken at the consumer unit,your full load perhaps up to 32amp would have to flow through the 2.5mm cable,which isn't rated to carry this load,causing overheating and thus a possable fire risk where the rat has made its nest with the sawdust and debris from the electrician cutting his holes in the joists and forgetting to clean up.

 

[lawsonium]

Interestnig stuff mrloy99, I haven't spent much time studying the system, only a quick look around, I intend to get to this and really concentrate on what's what when I've finished more of the structural work.

sorry,didn't realize you had existing lights out there.
Not sure what set up you have there,if you only have one c.u.
The ones I've seen before have twne for ordinary tarriff and another for off peak.Maybe the whole lot is on a dual tarriff supply.

My first thought was that 2 CU's wuold be sensible but there isn't. I will take a picture tonight and put it up for yuo to have a look at. I'll try and describe as much of the systyem as I can too.

Thanks,

Matt.

 

[lawsonium]

Hi there,

Sorry it's taken me a few days to get this to you. Been very busy working on the house. Replacing lead pipes with plasic, fixing dodgy joints in clay waste pipes, getting the plastering done, sanding floodboards etc etc etc...

Here is a picture of my switch box, if you need me to enlarge anything or describe the wiring of anything, please let me know. Any comments about this setup and how to improve it will be greately appreciated.

Regards,

Matt.

 

[mrloy99]

Hi there,

Sorry it's taken me a few days to get this to you. Been very busy working on the house. Replacing lead pipes with plasic, fixing dodgy joints in clay waste pipes, getting the plastering done, sanding floodboards etc etc etc...

Here is a picture of my switch box, if you need me to enlarge anything or describe the wiring of anything, please let me know. Any comments about this setup and how to improve it will be greately appreciated.

Regards,

Matt.

Hello Matt,
I would suggest that you post this as I new thread starter as this is all getting a bit long winded and off topic.(but you should be bringing things up to 17th spec if you are doing major renovations at this time)