RDB85

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Trainee
Basically I’ve attended a friend house who asked me to see why his power to his sheds had stopped working. Any help or advice on fixing this mess please
 

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So is RCD tripping?
Obviously cracked box, SWA not earthed this end, and B32 possibly feeding two radials (or is it a RFC?)

All I'd care about is understanding the reason why it doesn't work, and then whether the incoming SWA is sound. IR test it, continuity test it. I'd assume the other end is a fuse or MCB?

Then I wouldn't want to do anything other than start again. From what you've shown I've two instant ideas:
You could fit a little IP65 CU, re-terminate the SWA into that (but earth it), and fit a couple of B16 RCBO's, one for each shed.

Or you could re-terminate the incoming SWA into a galv besa box, or resin joint, extend the SWA and and fit a little garage CU inside the shed.
He could have some lights then as well.
 
So is RCD tripping?
Obviously cracked box, SWA not earthed this end, and B32 possibly feeding two radials (or is it a RFC?)

All I'd care about is understanding the reason why it doesn't work, and then whether the incoming SWA is sound. IR test it, continuity test it. I'd assume the other end is a fuse or MCB?

Then I wouldn't want to do anything other than start again. From what you've shown I've two instant ideas:
You could fit a little IP65 CU, re-terminate the SWA into that (but earth it), and fit a couple of B16 RCBO's, one for each shed.

Or you could re-terminate the incoming SWA into a galv besa box, or resin joint, extend the SWA and and fit a little garage CU inside the shed.
He could have some lights then as well.

Yes the RCD has tripped. It’s feeding two radials of 4mm 3 core NYY to each shed. Which has its own light, socket and FCU. The other end of the cable is a 40a MCB.

I’ve got a Wiska 1010 box and a Vent Plug, if the SWA is no good I may replace with NYY so it’s all the same cable. Would this need to be earthed with an Earth locking nut on that end?

Also replace the connector block with 222 Wago?
 
You don't replace a cable so it matches the other you replace it with a suitable cable. NYY-J does not need an earth lock nut. I'm not sure you are experienced enough to be undertaking such things without supervision.
 
Yes the RCD has tripped.
As bad as that lot looks, the reason could be downstream of there. You need to IR test the two radials in turn.

if the SWA is no good I may replace with NYY so it’s all the same cable. Would this need to be earthed with an Earth locking nut on that end?
Does the SWA have a cable route where it would otherwise need RCD protection at source? You may need to consider this before changing cable type.

Wagos? Yes!
 
You don't replace a cable so it matches the other you replace it with a suitable cable. NYY-J does not need an earth lock nut. I'm not sure you are experienced enough to be undertaking such things without supervision.

What I’m saying is if the SWA is no good. I’m going to replace it with NYY-J Meaning it’s the same cable type used throughout the installation.
 
As bad as that lot looks, the reason could be downstream of there. You need to IR test the two radials in turn.


Does the SWA have a cable route where it would otherwise need RCD protection at source? You may need to consider this before changing cable type.

Wagos? Yes!

The SWA runs into the Garage Consumer unit. It’s on its own MCB. What would be best used to connect the two boxes together. Something like a Brass Compression Gland.
 
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So is RCD tripping?
Obviously cracked box, SWA not earthed this end, and B32 possibly feeding two radials (or is it a RFC?)

All I'd care about is understanding the reason why it doesn't work, and then whether the incoming SWA is sound. IR test it, continuity test it. I'd assume the other end is a fuse or MCB?

Then I wouldn't want to do anything other than start again. From what you've shown I've two instant ideas:
You could fit a little IP65 CU, re-terminate the SWA into that (but earth it), and fit a couple of B16 RCBO's, one for each shed.

Or you could re-terminate the incoming SWA into a galv besa box, or resin joint, extend the SWA and and fit a little garage CU inside the shed.
He could have some lights then as well.
Slightly off topic but this has intrigued me for ages, you state "B32 possibly feeding two radials" as that's what it looks like but I don't believe that device has any over current protection at all, its just an RCD with contacts rated to 32A just like the 63A and 80A RCD's we so often see in consumer units.

The bit that intrigues me is why would manufacturers make an RCD that is only rated to 32A when they produce so many that are 63/80/100A rated. what could it possibly be used for that a vastly more common higher rated one couldn't be. All it does is confuse people into thinking its got some kind of over current protection, I'll bet there are hundreds of these devices installed for just that purpose.
 
Slightly off topic but this has intrigued me for ages, you state "B32 possibly feeding two radials" as that's what it looks like but I don't believe that device has any over current protection at all, its just an RCD with contacts rated to 32A just like the 63A and 80A RCD's we so often see in consumer units.

The bit that intrigues me is why would manufacturers make an RCD that is only rated to 32A when they produce so many that are 63/80/100A rated. what could it possibly be used for that a vastly more common higher rated one couldn't be. All it does is confuse people into thinking its got some kind of over current protection, I'll bet there are hundreds of these devices installed for just that purpose.

I've seen quite a few showers which were later additions to installations and fed from a '63A' RCD. Presumably the installer laboured under the misapprehension that this rating represented overcurrent protection.

On your later point I've often wondered if it wouldn't be cheaper for manufacturers to produce only one current rating, rather than a range - 100A being the obvious suggestion. Small 'garage' boards often have an RCD mainswitch rated at 40A. 16A 3ph RCD protected interlocked sockets are often supplied (if indeed an RCD is supplied) with 25A devices. All of these are perfectly acceptable and fit for purpose, but their availabilty suggests there must be a commercial reason for offering a wide range - just not one that is obvious to me.
 
I’ve got a Wiska 1010 box and a Vent Plug, if the SWA is no good I may replace with NYY so it’s all the same cable.

How is the SWA installed and how would your proposed new NYY be installed?

There's a lot more to selecting the right cable for the job than just making it all the same type.

Would this need to be earthed with an Earth locking nut on that end?
Is this a trick question? NYY doesn't have any armour to earth.
 
How is the SWA installed and how would your proposed new NYY be installed?

There's a lot more to selecting the right cable for the job than just making it all the same type.


Is this a trick question? NYY doesn't have any armour to earth.

The SWA goes into the L N terminals on the RCD. It’s then fed into the Garage Consumer Unit on an MCB. Then the Garage has its own feed back to the Consumer unit in the house. It’s currently buried under paving in the garden.

The new NYY-J would be installed in Galvanised Conduit.
 
The SWA goes into the L N terminals on the RCD. It’s then fed into the Garage Consumer Unit on an MCB. Then the Garage has its own feed back to the Consumer unit in the house. It’s currently buried under paving in the garden.

How would the proposed NYY-J replacement be routed back to that consumer unit?
 
Slightly off topic but this has intrigued me for ages, you state "B32 possibly feeding two radials" as that's what it looks like but I don't believe that device has any over current protection at all, its just an RCD with contacts rated to 32A just like the 63A and 80A RCD's we so often see in consumer units.
You make a good point, I wondered that after I wrote it.
@RDB85 if you look up the CCC I would think the 4mm NYY-J’s tabulated value is lower that 40 amps. (I haven’t checked)

I’d back track a bit and do some testing - the SWA is not going to cause a downstream device tripping and is likely fine.
(If I was going to run galv conduit I wouldn’t be pulling NYY-J through it)
 
Via conduit.
Galv conduit would certainly provide good mechanical protection. @timhoward raises the issue of CCC - I don't know the differences between SWA and NYY off the top of my head, nor the correction factor when enclosed in conduit, but you may need to increase cable size and also that of the conduit. Seems like quite a bit of additional cost for something that isn't known to be faulty.
 
Right so I’ve done some further investigation back at the consumer unit in the garage. Tested for Continuity and IR and got nothing. Open up the Consumer unit to find that when it was converted into a room. They decided to cut it. So the feed that goes from there to the RCD is no more.

The NYY-J is what was left over from the previous installation for both shed radials.
 
You make a good point, I wondered that after I wrote it.
I had the same problem a few months ago, my mate was looking at some wiring in a food wagon and he rang me for advice on what to do next, he says there is a 32A RCD protecting the installation without any breakers and I said well if its a 32A RCD then it must be an RCBO so its covered but he was adamant it was just an RCD, when he sent me a picture and I looked a bit closer it dawned on me that it was indeed just an RCD.

If it said 63A or 80A etc the you would automatically assume its just an RCD without any other protection, its just the fact that it has a low value on it that I think loads of people will think its an MCB as well, same as the 20A and 25A ones that are also knocking about. Just doesn't make any sense to me to have all that different tooling to make different rated RCD's when a 100A would cover everything, the cost on saved metal must be minuscule.
 
I had the same problem a few months ago, my mate was looking at some wiring in a food wagon and he rang me for advice on what to do next, he says there is a 32A RCD protecting the installation without any breakers and I said well if its a 32A RCD then it must be an RCBO so its covered but he was adamant it was just an RCD, when he sent me a picture and I looked a bit closer it dawned on me that it was indeed just an RCD.

If it said 63A or 80A etc the you would automatically assume its just an RCD without any other protection, its just the fact that it has a low value on it that I think loads of people will think its an MCB as well, same as the 20A and 25A ones that are also knocking about. Just doesn't make any sense to me to have all that different tooling to make different rated RCD's when a 100A would cover everything, the cost on saved metal must be minuscule.

I'm not sure why some people make this assumption, but it certainly calls their competence into question.

Would they make similar assumptions about the rating of an isolator?
 
With that now the culprit. I’ve ordered a vent plug for the Wiska Box. Some Wago 222 Connectors and something to connect the Wiska Box and RCD enclosure.

In hindsight singles would probably be better but I’ve got 30m of NYY and the price of cable and also selling the NYY.
 
I had the same problem a few months ago, my mate was looking at some wiring in a food wagon and he rang me for advice on what to do next, he says there is a 32A RCD protecting the installation without any breakers and I said well if its a 32A RCD then it must be an RCBO so its covered but he was adamant it was just an RCD, when he sent me a picture and I looked a bit closer it dawned on me that it was indeed just an RCD.

If it said 63A or 80A etc the you would automatically assume its just an RCD without any other protection, its just the fact that it has a low value on it that I think loads of people will think its an MCB as well, same as the 20A and 25A ones that are also knocking about. Just doesn't make any sense to me to have all that different tooling to make different rated RCD's when a 100A would cover everything, the cost on saved metal must be minuscule.
I suppose everything has a price point. It could be quite a bit more expensive overall to manufacture a 100A rated RCD compared to a 25A

So the manufacturer only making 100 A RCDS would be competing on price against the 25 32 40 and 63 manufactured by others
 
With that now the culprit. I’ve ordered a vent plug for the Wiska Box. Some Wago 222 Connectors and something to connect the Wiska Box and RCD enclosure.

In hindsight singles would probably be better but I’ve got 30m of NYY and the price of cable and also selling the NYY.
Other than having been disconnected is there anything wrong with the existing cable?
 
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Hmm as an electrician I tend to check the source of power 1st and then work from there. You also seem convinced that you need to run a new cable...but only in your last post do you state/imply that the armour cable has been cut "somewhere".
If something is outside your normal work/comfort zone sometimes it is better to just accept it and get a person in that knows this type of work well.
Not knowing how to do something isn't embarrassing or anything like that, But winging it and guessing is wrong on so many levels. You could get someone in and even learn from them for next time.....
 
Hmm as an electrician I tend to check the source of power 1st and then work from there. You also seem convinced that you need to run a new cable...but only in your last post do you state/imply that the armour cable has been cut "somewhere".
If something is outside your normal work/comfort zone sometimes it is better to just accept it and get a person in that knows this type of work well.
Not knowing how to do something isn't embarrassing or anything like that, But winging it and guessing is wrong on so many levels. You could get someone in and even learn from them for next time.....

It’s a bit obvious that a new cable is needed as it’s anyone’s guess as to where it’s been cut. Maybe as the RCD was off I also decided to look in the enclosure. As you know it’s outside and all.

Having done that and then trying the consumer unit I then found the problem. I’m not trying to wing it or guess it. I’ve a Level 2 and 3 2365 so I’m okay with having some knowledge.

I could get someone in but most of the sparks I know feel confident that I could do that myself.
 
I’m not trying to. But you really don’t like anyone that works in that field. Also the original install was done by a qualified spark. What’s wrong with NYY or do you have a better suggestion.

It was a tongue in cheek post, but not entirely inaccurate.

Your suggestion of replacing the cable cable prior to the apparent discovery that it has been cut. You reasoning behind using NYY was based on 'having all cable of the same construction' and later 'because you had some to sell'. I'd love to understand the reasoning behind all of this, but accept that I'll never know the facts.

As for what I'd do? Well I'd make decisions based on what exists and what needs to be achieved. The very things people have been trying to learn from you since yesterday, but apparently you're only bringing you make that assessment after already deciding on part of a planned way forward.
 
It’s a bit obvious that a new cable is needed as it’s anyone’s guess as to where it’s been cut. Maybe as the RCD was off I also decided to look in the enclosure. As you know it’s outside and all.

The posts in this thread indicate you knew this was obvious a whole day before learning the cable has apparently been cut.

Incredible foresight on your part
 
It was a tongue in cheek post, but not entirely inaccurate.

Your suggestion of replacing the cable cable prior to the apparent discovery that it has been cut. You reasoning behind using NYY was based on 'having all cable of the same construction' and later 'because you had some to sell'. I'd love to understand the reasoning behind all of this, but accept that I'll never know the facts.

As for what I'd do? Well I'd make decisions based on what exists and what needs to be achieved. The very things people have been trying to learn from you since yesterday, but apparently you're only bringing you make that assessment after already deciding on part of a planned way forward.

Okay so what currently exists is an RCD and an outside box. Two radials done in 4mm NYY. And a 1.5mm SWA that’s been cut. I’ve 30m of NYY which I’ve decided to use as selling it online is a right pain and with the price of cable going up it’s not worth buying new cable when the NYY seems appropriate cable to use.

I’ve also got some 25mm Galv Conduit and an assortment of Saddles and End and Through Boxes.

All I’m doing is asking for some advice and trying to help a friend restore power to his sheds.
 
Okay so what currently exists is an RCD and an outside box. Two radials done in 4mm NYY. And a 1.5mm SWA that’s been cut. I’ve 30m of NYY which I’ve decided to use as selling it online is a right pain and with the price of cable going up it’s not worth buying new cable when the NYY seems appropriate cable to use.

I’ve also got some 25mm Galv Conduit and an assortment of Saddles and End and Through Boxes.

All I’m doing is asking for some advice and trying to help a friend restore power to his sheds.
I'm all for trying to draw a line as many on here would like to help you. My gentle suggestion is to just admit mistakes and move on. It's not like we don't all make mistakes too. I'm sure you've already learned things from this. e.g. assume nothing and work methodically when fault finding (find out what does work first)

So, you currently have a B40 device for the supply circuit. Is this RCD protected in the garage board or not?
Have you got a cable that's CCC exceeds 40 amps after appropriate deratings?
Until you have the supply circuit design sorted you can't move on to the details.

Brief research shows that 4mm NYY-J clipped direct is rated under 40 amps, so by the time it's in galv conduit I'd doubt this is going to cut it. So you may need to rethink the protective device and/or the cable.
Does that get you started?
 

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RDB85

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