Consumer Unit Tales

[electrics_new]

Hi All,

I have the following situation and any advise would be appreciated.

Customer wanted external security lights installed - some outside low voltage garden lights and - provide electricity to an external garage.

Customer wanted a new DB installed with dual RCD.  However, customer wanted to keep the existing board installed as well.  This way any new circuits installed would go into the new board with an RCD.

Issue is that the place where the existing DB is installed - space is very, very limited and access is very difficult.

I installed the new board - isolated the power and attempted to connect the 25mm tail ends into the 100amp junction box. Which feeds the existing DB and houses the meter tails.

I physically can't install - due to space an additional two new tail ends into the 100AMP junction box.  This is no way I can bend the tails to fit.  The existing meter tails are also way to short.

I was thinking that because the new DB doesn't have much load I can use a smaller gauge cable - for example 12mm or 16mm.  

The new DB only has installed:  x1 6amp MCB, x2 32 amp MCB's - which will hardly be used.

Please advise.  Can I use a smaller cable to connect to new DB to 100amp junction box.

thanks in advance.

 

[binky]

16 would be fine, no real load on tails to merit 25mm. You could go lower, but its hard to find smaller size tails these days.

 

[Evans Electric]

Don't forget the Service Fuse protects the tails but lets be honest ...16mms would be fine if you can get them in . 

Can't you dismantle the 100A block ..fit all the tails to it and then fix it back again ?   Or fit the block further back on the main tails?

 

[ProDave]

A picture would be nice.

16A tails seem to be rated at 87A and lets be honest, there must be millions of houses using 16A tails for the full house load without issue.

But it does sound like a typical half baked scheme to keep the old CU and add a new one, when a better solution would have been a new decent sized CU. I presume this decision was the customer not willing to pay for that? 

 

[Andy™]

i expected to find a story about a consumer unit in here.... mis-leading title!

 

[ProDave]

i expected to find a story about a consumer unit in here.... Miss Spelled  title!

I've corrected that for you.

 

[steptoe]

mmmmm

are you a spark?

just wondering as 12mm tails is something Ive not only never used,

but never heard of.

:|

Im really not sure you should even be doing this sort of thing if you cant calculate cable sizes TBH, or you use mythical sizes,

 

[steptoe]

Dont you know anything :slap

AWG 6.5 msl:

not a lot

but,

I do know AWG6.5 isnt 12mm ,  bit like 3/8 isnt 11mm [or 10] ,

the one I love though is a guy I know that says a metre is 3.3feet but cant understand why its actually closer to 3' 4"  :slap

 

[Robin Spark]

Had a new car last week and took daughter swimming where i parked up reversing close to a wall.

My daughter got out of the car and said " daddy your 3 feet away from the wall!"

I thought no i am not? I am much closer than that.

She then demonstrated the distance by putting one foot infront of the next three times hehe.

Well she is only 7 yrs old!

 

[SLIPSHOD & SLAPDASH]

Why is this not in the DIY section   ;    customer  my arse.

 

[SPECIAL LOCATION]

Sounds like one complete new CU would have been easier than all this messing around...

time is money?

or isn't the customer paying for your time??

How come this wasn't spotted when you assessed the job at design stage??

its not rocket science to know how much of a radius bend you can stuff on a 25mm tail???

Best solution...

Call an electrician!

opcorn