Discuss 40a MCB to 2 gang socket - want to spur off to FCU at 13a for freezer over winter in the DIY Electrical Advice area at ElectriciansForums.net

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Hello everyone,

We had an electrician over, who fitted a 40a MCB in the house consumer unit to supply a new build garage. It's underground SWA, in conduit also. He temporarily fitted a 2 gang socket so we could use power tools whilst we complete a fitout internally, although in that use case, the socket is only in use whilst it is attended.

As the weather has changed, work is coming to a partial halt. We now have a requirement to place an upright freezer in the garage over winter.

I hope I am correct in thinking it is unwise to plug a freezer with a plug fused to 13a into the double socket and leave it unattended 24/7. If the plug fuse were to fail, I feel there is potential for an unnoticed fire.

My plan is to spur off the 2 gang socket and fit an FCU fused at 13a and then wire the freezer into that FCU. The 2 gang which supplies the spur will be in attended use only during this time, mostly for LED lighting but occassionally a saw at around 8a.

Is doing that considered safe? Logic tells me it should be, but I do realise it is no substitute for a CU being fitted, which is coming in spring.

Many thanks as always
 
Just use the socket that is there it will be fine.

Thanks westward10. I guess I missed something rather crucial in that one of the sockets is in use 24/7 for the garage doors and the other for temporary lighting/power tools, so I need 1 extra socket for the freezer. Sorry :D
 
Cheers westward10. Unfortunately the electrician cant come now until January, so we're a bit stuck. If a spur is unsafe (I know its not ideal), I can feed the supply into a junction box and wire a couple of 2 gangs at 13a off that. I have (dare I say) sufficient knowledge of how to physically wire things properly and correct tools, I'm just not familiar with the entirity of the current regs and tend to err on the side of caution when it comes to electricals.
 
It isn't exactly conventional but it just needs another socket from the existing one, what size of cable was put in?
Alternatively a good quality four way extension lead fitted to the wall.
 
Use a double socket or 4 way short extension.
you will come to no harm.
 
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It isn't exactly conventional but it just needs another socket from the existing one, what size of cable was put in?
Alternatively a good quality four way extension lead fitted to the wall.

Supply is 6mm SWA I think. Haven't verified yet and electrician can't remember precisely. It makes sense to me [and him] but I'll check before doing anything.

Use a double socket or 4 way short extension.
you will come to no harm.

Is short considered something under 5m? We have a 50m extension on one of the sockets at the moment powering 3x 10W LED and 1 power tool, circa 8a (it is switched off at the socket when we leave). The other socket is permanently occupied by the garage doors.

Theres a bit of an issue with heights, as the current socket is at about 2.1m, whereas the flex on the freezer is around 1.5m, so we need to bring any supply down to the freezer level. (Mindful of trip hazards here too)

I feel like, from both yours and westward10's replies, there is no inherent safety risk if I place a [metal] junction box and supply 2No. 2 gang sockets from it. It means I can install correct glands for the SWA on the junction and complete the remaining using 2+e wire in plastic conduit to metal surface fix. The twins wont be fully armoured, but for the moment there is no risk of cable damage in that area, as it is unused. Longer term, it will all be steel conduit and surface fix metal.

Am I good doing that?

Thank you for your time, it is MUCH appreciated, both of you.
 
You don't need a junction box, assuming the cable is no more than 6.0 just connect another socket at a level suitable for the freezer.
 
Supply is 6mm SWA I think. Haven't verified yet and electrician can't remember precisely. It makes sense to me [and him] but I'll check before doing anything.



Is short considered something under 5m? We have a 50m extension on one of the sockets at the moment powering 3x 10W LED and 1 power tool, circa 8a (it is switched off at the socket when we leave). The other socket is permanently occupied by the garage doors.

Theres a bit of an issue with heights, as the current socket is at about 2.1m, whereas the flex on the freezer is around 1.5m, so we need to bring any supply down to the freezer level. (Mindful of trip hazards here too)

I feel like, from both yours and westward10's replies, there is no inherent safety risk if I place a [metal] junction box and supply 2No. 2 gang sockets from it. It means I can install correct glands for the SWA on the junction and complete the remaining using 2+e wire in plastic conduit to metal surface fix. The twins wont be fully armoured, but for the moment there is no risk of cable damage in that area, as it is unused. Longer term, it will all be steel conduit and surface fix metal.

Am I good doing that?

Thank you for your time, it is MUCH appreciated, both of you.

Change of plan, I'll high level mount a plastic Wiska junction box for the SWA after seeing the price of the metal ones. lol
 
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You don't need a junction box, assuming the cable is no more than 6.0 just connect another socket at a level suitable for the freezer.

OK, I'm glad. Just updated my post after realising the price of the metal ones! Don't mind spending a good few quid on final install, but ouch. It's not even my freezer! lol

Sorted then. I'll run some 2.5mm3 cable in plastic (for now) conduit down from the existing 2 gang and into a 1 gang at correct floor level for the freezer.


Thank U Reaction GIF by Amanda
 
Seems to be getting very complicated to plug in a freezer.
try this for size.
https://www.NoLinkingToThis/p/masterplug-13a-4-gang-unswitched-extension-lead-1m/8935g
 
Seems to be getting very complicated to plug in a freezer.
try this for size.
https://www.NoLinkingToThis/p/masterplug-13a-4-gang-unswitched-extension-lead-1m/8935g

I think its sorted now. I couldn't use something like that due to the levels and whats being used currently. It's hard to properly explain the exact circumstances without writing an essay and I havent got a pic to hand. I got there though guys, appreciate it. I am confident theres no risk in what I was thinking of doing, thanks to you guys.
 
Change of plan, I'll high level mount a plastic Wiska junction box for the SWA after seeing the price of the metal ones. lol
As @James says you are over complicating this which people without sufficient competence do, get an extension lead.
 
Last edited:
As @James says you are over complicating this which people without sufficient competence do, get an extension lead.

I have been well informed by your replies. Totally confident going forward now. Extension lead would present a hazard if left in (semi) permanently, because of the location of the supply. I should probably have taken a picture but thought it was more a theoretical question I was asking. It's quite difficult for me to form a question properly when you don't know my experience level or the circumstances of the install, risks running to pages.

Next time I'll bring a photo.

I appreciate all your help and you can be assured I'm not going to blow anything up :)
 

Reply to 40a MCB to 2 gang socket - want to spur off to FCU at 13a for freezer over winter in the DIY Electrical Advice area at ElectriciansForums.net

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