Junction Box

[Poisonata]

I'm planning on adding an extra double socket in our spare room (bedside lamp and phone charger) while we are decorating. My plan was to insert a junction box into an existing cable that very conveniently runs exactly past the new socket location. Tracing the cable to it's end point it appears to feed a double socket that operates the washer and tumble dryer. The dryer has a rating of 4.2 kWh.
My questions are:
1. Is a standard 30 Amp junction box adequate.
2. Knowing this cable feeds two appliances that consume quite a bit of power, would this be a poor choice of cable to tap into.
My thanks in advance to any responders.

 

[JohnW2]

The first two crucial questions are where that cable comes from and what size cable it is.

Kind Regards, John

 

[Poisonata]

It is 2.5 sq mm twin and earth BASEC (old colours red/black). The copper wire cores are solid. Standard wire for socket outlets.

From the consumer box (MK Sentry 10 Way Dual RCD Board with 2 RCDs & 10 MCBs) the wire also powers the gas boiler control box/pump.

Consumer unit > Gas Boiler > (potential new junction box) > Washer & Dryer (end of wire)

Apologies for not including this information in my original post.

 

[JohnW2]

It is 2.5 sq mm twin and earth BASEC (old colours red/black). The copper wire cores are solid. Standard wire for socket outlets. From the consumer box (MK Sentry 10 Way Dual RCD Board with 2 RCDs & 10 MCBs) the wire also powers the gas boiler control box/pump.
Consumer unit > Gas Boiler > (potential new junction box) > Washer & Dryer (end of wire)

Do I take it that it comes straight from the CU and only supplies the things you've mentioned (boiler/CH and double socket for WM & dryer)? If so, what size/rating does the relevant MCB in the CU have?

Kind REgards, John

 

[Poisonata]

MK 5932S Sentry 32 Amp Type B 6ka Single Pole MCB.

The wire does only feed the aforementioned items.

Thank you for your responses so far.

 

[JohnW2]

MK 5932S Sentry 32 Amp Type B 6ka Single Pole MCB.

OK. So, for starters, what you have at the moment is not acceptable. It is neither safe nor compliant with regulations to have 2.5mm² cable protected by a 32A MCB - this circuit was presumably not installed by an electrician? Unless you replace the cable with 4mm² , the MCB should be downrated to 20A (conceivable 25A, if one is available for your CU and the way in which the cable is installed allows use of such an MCB). However, that 20A will probably then not be enough for your WM and dryer, if they were used simultaneously - so upgrading to 4mm² cable might be the only proper option.

Once the current circuit had been sorted out, as above, then to do as you proposed for the new socket would probably be OK.

Kind Regards, John

 

[ban-all-sheds]

The dryer has a rating of 4.2 kWh.

That's not a rating which is of any use in determining what current the dryer draws. It tells you how much energy it uses to perform a particular drying task. A GU10 LED lamp could use 4.2kWh if you left it on for 43 days and 18 hours, so could a powerful electric shower in 20 minutes.