Why can't you join 6mm and 2.5mm?

[philectrical]

Saw this thread in the DIY forum but can't respond and i have a question:

We are getting our bathroom refurbished , our bathroom already had a 9.5kw shower we are getting that changed to a rainfall shower.
As we have low water pressure we are having a water pump installed.

The builder has connected the existing 6mm cable to 2.5mm cable (using a connector block ) for the socket for the water pump.

Is this safe ?

Everyone seems to be going mad in the thread suggesting it's dangerous but this seems fine to me.

Since it's only a pump now, as long as the MCB is downrated to a max of 20a it should be fine, no?

Sorry if it's a stupid question but i'm a trainee and just getting to grips with all the science.

 

[westward10]

The reason it was considered dangerous was because our multi-talented builder jointed it by way of unenclosed block connectors. This is the thread in question.

is it safe to connect a 6 mm cable to a 2.5mm cable - in - DIY Electrical Advice

, is it safe to connect a 6 mm cable to a 2.5mm cable, DIY Electrical Advice, ElectriciansForums.net Est.2006 | Free Electrical Advice Forum and page_number.

www.electriciansforums.net

 

[littlespark]

Yes, as Westy says.
That particular thread, the builder had reduced the csa of the cable, but hadn’t downgraded the mcb to suit.
It is explained throughout the thread that reducing it to a 20A supply would solve the issue.

 

[philectrical]

It is explained throughout the thread that reducing it to a 20A supply would solve the issue.

Where? Didn't see that

 

[DefyG]

20A!! what size pump is being used? A 6A mcb would probably be more than adequate for a shower pump.
The cable joint needs to be within a propriety enclosure, and maintenance free if inaccessible.