RE: 2-way CU meter tails

[Ahtyrrell]

Just to provide a useful response to the OP rather then useless drivel, while 6mm would probably satisfy your load and may technically be safe as the upstream OCPD would operate before the cable could become overloaded.

Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use in this scenario, 16mm would be more then adequate, the idea of splitting the tails into a sub CU is also very sensible

 

[PrenticeBoyofDerry]

Just to provide a useful response to the OP rather then useless drivel..............

Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use

So how do credit your response as useful?
The most useful response to be given would be source a competent electrician, as I doubt that they already had one in mind or had made contact with one.
The guy was/is a chancer, didn't get the response they wanted then got abusive, can do without that type!

 

[Ahtyrrell]

Just to provide a useful response to the OP rather then useless drivel..............

Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use

So how do credit your response as useful?
The most useful response to be given would be source a competent electrician, as I doubt that they already had one in mind or had made contact with one.

How is it not useful it gives the OP the information that he wanted about the correct cable to use

 

[PrenticeBoyofDerry]

How is it not useful it gives the OP the information that he wanted about the correct cable to use

But have you?

 

[RF Lighting]

Just to provide a useful response to the OP rather then useless drivel, while 6mm would satisfy your load and would technically be safe as the upstream OCPD would operate before the cable could become overloaded.

Have a search for "fault current".

Overload is not the only thing to consider when sizing cables.

 

[Steve]

Just to provide a useful response to the OP rather then useless drivel, while 6mm would satisfy your load and would technically be safe as the upstream OCPD would operate before the cable could become overloaded.

How do you know this? Do you know the EFLI? Do you know the rating of the OCPD? Do you know what type of earth the OP has? Do you know the length of run? Do you know if the cables are grouped? Do you know if they run in insulation at any point?

No.

No you do not.

The problem you have here is that the OP may read your reply, take it as gospel, then he has a fault and his house burns down because you gave him the wrong advice on the cable he can use. (worth pointing out too that most DIY installs are specced based on cost of materials, so he is probably wanting to use 6mm because he either has some knocking about after he fitted his shower illegally or just because its cheaper, either way it probably won't be DI for its entire run.)

Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use in this scenario, 16mm would be more then adequate, the idea of splitting the tails into a sub CU is also very sensible

The problem again is that you have already told him he can use 6mm and everything will probably be ok, which he will read as everything will be definitely ok.

 

[EFLImpudence]

... while 6mm would satisfy your load and would technically be safe as the upstream OCPD would operate before the cable could become overloaded.

Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use in this scenario,

16mm would be more then adequate,

the idea of splitting the tails into a sub CU is also very sensible

I would say that is most unhelpful.

I agree with PBoD.

 

[RF Lighting]

Looks like we all do....

 

[Ahtyrrell]

He asked a question about cable sizes and I answered it if he uses 16mm there will be no problem it doesn't matter what the earthing system is as to the size of the line and neutral tails yes that is a consideration for other things but as far as the question he asked goes then he now has an answer, if he chooses to ask about other things such as earthing systems then they can be answered separately

I can not imagine a set up where two adjacent CUs have cables running through insulation not like he is putting the new CU at the other end of the house

 

[Ahtyrrell]

Just to provide a useful response to the OP rather then useless drivel, while 6mm would satisfy your load and would technically be safe as the upstream OCPD would operate before the cable could become overloaded.

Have a search for "fault current".

Overload is not the only thing to consider when sizing cables.

I know that hence the "Probbably" and the fact that I do not advise 6mm cable and instead told him to go with 25 or 16 which will be sufficient in any domestic situation with an 80/100 amp main fuse

 

[RF Lighting]

But you said in your first post 6.0mm² tails would be safe to use.

Now you're saying 16.0mm²

I don't see how giving two different answers, and one of them incorrect is particually helpful?

 

[Steve]

He asked a question about cable sizes and I answered it if he uses 16mm there will be no problem it doesn't matter what the earthing system is as to the size of the line and neutral tails

Maybe, but in your OP you wrote:

Just to provide a useful response to the OP rather then useless drivel, while 6mm would satisfy your load and would technically be safe as the upstream OCPD would operate before the cable could become overloaded.

Despite the fact that you know none of the other parameters of the installation as I outlined above.

And the DIYer (dunno his name) will read that as:

You can use 6mm and everything will be hunky dory

Anything you say after that will be irrelevant.

 

[Ahtyrrell]

Sorry if there was a misunderstanding I was trying to say that as the OP calculated 6mm cable would satisfy the load of the new consumer unit however to be on the safe side 16mm tails should be used.

This is a DIY forum and if someone askes a question then cherry picks the wrong bits of advice and does a poor install then its there problem, on the other hand he may use the advice given complete the install with the correct cable/materials and there is no problem

 

[Taylortwocities]

Ahtyrrell, what the f…… does this relate to????. is there some other topic with more information?
The general idea is that you would make your comments as part of that topic, rather than start another separate one.

Even a link to the original thread would be useful.

 

[Steve]

I wouldn't want it on my conscience if he burnt his house down because he supplied his new CU with 6mm cable on my advice and a fault occurred . . .

Think like a DIYer. You are DIYing because money is tight. You have some 6mm cable, a qualified spark on the internet has told you it is OK to use but bigger would be better. Do you go out and spend another £20 on cable, or do you just use the 6mm cable?

If you, as the qualified spark advising, don't know the parameters of the installation required to make these assumptions, you should not make them and err on the side of caution.