16 AMP Upgrade...Completed

[PeteG]

I was hoping the Jet P/T would be here today but it's not to be. I'm having a 16 AMP socket put in this Saturday by a friend who's a lift engineer, he hasn't done one of these before but these are the items I've bought.
So the question is, does it all look present and correct?

This is the fuse box in the garage, the black cable on the left is the supply from the house.



I've bought two 32 amp fuses, one will replace the 16 amp in the house as it always trips when I turn the Dewalt table saw on, that's 1800 watt.
The second 32 amp fuse apparently will replace the RCD VR40 on the left in the above image.



From the fuse box he'll them connect 10 mm cable.



On the end of which will be a 16 amp socket.

 

[sploo]

Difficult to say - does that mean you won't have any RCD protection for your 13 amp mains sockets? (that would be a bad idea)

If the table saw is tripping a 16 amp MCB in the house I'd be worried about the saw. I assume it's just connected to a standard mains socket (meaning it shouldn't take more than 13 amps even when starting).

It's not clear to me to which MCB your 16 amp socket is going to be connected. I'd suspect it shouldn't be hooked up to a 32 amp.

Last time I looked, I thought you were OK to make mods in the garage without falling foul of Part P rules (http://www.electricalsafetyfirst.org.uk ... an/part-p/) but it might be worth checking up on this (or, frankly, if you're at all unsure with electrics - get an electrician in).

 

[Wuffles]

A dirty fix is:

Take out the lights MCB and replace it with the one you intend to use for the 16A circuit, then reroute the lighting circuit off the standard ring through a fused spur with a 6A fuse in it.

The proper way would be to swap out the consumer unit for something large enough to take the RCD and the required amount of MCBs.

Not sure what you've spend so far on MCBs, but get yourself to a local Denmans (as an example as it's who I use and don't appear to be in the racket of ripping off the punter off the street) and you could probably have got a larger consumer unit fully populated for not much more money. I recently swapped out a 3 port unit for a 6 port when I added a circuit as it was about the same cost as replacing a suspected faulty RCD in the original unit.

 

[PeteG]

Difficult to say - does that mean you won't have any RCD protection for your 13 amp mains sockets? (that would be a bad idea)

If the table saw is tripping a 16 amp MCB in the house I'd be worried about the saw. I assume it's just connected to a standard mains socket (meaning it shouldn't take more than 13 amps even when starting).

It's not clear to me to which MCB your 16 amp socket is going to be connected. I'd suspect it shouldn't be hooked up to a 32 amp.

Last time I looked, I thought you were OK to make mods in the garage without falling foul of Part P rules (http://www.electricalsafetyfirst.org.uk ... an/part-p/) but it might be worth checking up on this (or, frankly, if you're at all unsure with electrics - get an electrician in).

Hello Sploo

I've always had problems with anything of 1800 watt tripping the fuse inside the house, from the first Bosch mitre saw, to the Dewalt T/S and a Dewalt mitre saw, all 1800 watt. The Dewalt mitre DW777 was sent back a couple of months ago and I bought a Festool, 1600 watt, no problems. The annoying thing with the T/S, I can switch it on and all is fine, switch on again ten minutes later and it trips the fuse.

To answer your first question, the fuse board in the house has two RCD's.

Sorry, with questions I have asked in the past regarding electrics, I'm still baffled!

A dirty fix is:

Take out the lights MCB and replace it with the one you intend to use for the 16A circuit, then reroute the lighting circuit off the standard ring through a fused spur with a 6A fuse in it.

The proper way would be to swap out the consumer unit for something large enough to take the RCD and the required amount of MCBs.

Not sure what you've spend so far on MCBs, but get yourself to a local Denmans (as an example as it's who I use and don't appear to be in the racket of ripping off the punter off the street) and you could probably have got a larger consumer unit fully populated for not much more money. I recently swapped out a 3 port unit for a 6 port when I added a circuit as it was about the same cost as replacing a suspected faulty RCD in the original unit.

Appreciated Wuffles

 

[sploo]

The proper way would be to swap out the consumer unit for something large enough to take the RCD and the required amount of MCBs.

That's what I did when I sorted my garage some years ago - one with two distinct "lines" (I forget the correct terminology) so I could have a 32 amp RCD MCB for the mains sockets, and a non-RCD switched set for a 6 amp lighting and 20 amp line for my dust collector.

 

[sploo]

Hello Sploo

I've always had problems with anything of 1800 watt tripping the fuse inside the house, from the first Bosch mitre saw, to the Dewalt T/S and a Dewalt mitre saw, all 1800 watt. The Dewalt mitre DW777 was sent back a couple of months ago and I bought a Festool, 1600 watt, no problems. The annoying thing with the T/S, I can switch it on and all is fine, switch on again ten minutes later and it trips the fuse.

To answer your first question, the fuse board in the house has two RCD's.

Sorry, with questions I have asked in the past regarding electrics, I'm still baffled!

That's odd. Perhaps the house fuse is a bit too sensitive. You'll generally get a spike as a motor starts (inrush current) but it shouldn't be tripping things out unless it's too high for the fuse/MCB, or one part is faulty.
IRC some kit is best not hung off an RCD as it can trip when it shouldn't. However, having just checked my house consumer unit (a much newer professionally fitted one, after I did the garage), the garage is running off a 32 amp MCB, protected by an 80 amp 30mA RCD.

Memory fades - perhaps it was lights that were recommended not to be on an RCD, but anyway, technically everything in my garage is now hanging off an RCD in the house, so go figure. I am aware there are different types though; that respond in different ways.

 

[n0legs]

10mm T&E for 16 amp socket !! Well that's one cable that's not gonna' get hot.

Okay enough of the mirth from me.

Let me get some things straight.
In the house you have a fairly large consumer unit (CU) with upwards of 8 ways ?? This has 2 RCCD fitted, one looking after some circuits and the other looking after the others. The garage supply comes via a RCCD protected 16 amp MCB, down the Steel Wire Armoured (SWA) "black" cable to the garage CU?
In the garage protected by a 40 amp 30mA RCD, there are 2 circuits. One is lighting fed by a 6 amp MCB the other is "sockets" via a 40 amp MCB.
Why are your sockets protected by a 40 amp breaker, what kind of circuit is it, ring or radial, do you know the cable size?
Would you know the size of the supply cable (SWA) and what is the distance it runs?

I know it's all questions, but we need to know what you have there. There are right ways and wrong ways to achieve your goal, but most of all we need it done the safe way.

 

[Wuffles]

10mm T&E for 16 amp socket !! Well that's one cable that's not gonna' get hot.

Did your joke have a typo in it? Did you mean 1mm? I'm confused.

 

[mseries]

I am not an electrician, please take advice from someone who is. My Dad is an electrician and last year we replaced my garage CU so I could have a separate socket circuit for tools and one for other things such as the freezer. The tools one has a 20A MCB, the other one 16A. In addition there is a third circuit with a 6A MCB for the lights.

As far as I can see, and remember I an not an electrician, you have one cable entering your CU, the armoured black one and two exiting, the white conduit which I presume connects to the lights and sockets. The RCD on the left effectively shuts off the power to both of the MCBs in the CU, that is both of the circuits. You can test this, when you throw the switch do the lights and sockets go dead ? It's protecting both circuits from earth leaks. There will be no connections behind this to which you could connect the sockets as it's connected to the MCBs on it's right and to the mains input on it's left. Here is a picture of mine, it has no RCD, the large red on/off switch on the right is my Master (Main) switch. the three sets of copper sockets to it's left are where my MCBs plug in.



The mains comes from the inlet at the bottom, behinf the mounting plate and is connected at the top of the master switch. The from the middle and bottom of the master switch you can see the copper connecting the neutral and the live going through the MCBs
this picture shows the MCBs plugged in



I think you'll need to swap your CU for a three port one to get three circuits. As I said I am not an electrician so speak to someone who is for a proper response.

 

[Dee J]

So your supply to the garage is fused at 16 amps and you want to change that to 32? OK as long as the cable to the garage is adequate. Not sure what the B40 trip is doing in the garage box if it was supplied upstream by a B16 (or even by its replacement B32)? The garage RCD is unnecessary as its already covered by the house consumer unit RCD - but it does provide a good point of isolation. Given the garage will be fused at 32A in the house then a 32A socket circuit would need no further fusing - you could put your existing socket circuit straight onto the garage RCD output. Then why are you suggesting supplying a 16A socket with a 32A trip? Surely a 16 A one would be more appropriate? Even go to a C16 if tripping on startup is a problem (assuming the circuit checks out OK). And why 10sqmm cable? Unless its a very long cable run and you're trying to combat voltage drop its total overkill and a pain to install. 2.5sqmm is good enough, or maybe 4sqmm if the length of run demands it. And as a final note, mixing makes of MCBs in a consumer unit is frowned upon - voids any manufacturer liability - and they often won't fit properly due to differing busbar heights.

 

[mseries]

10mm T&E for 16 amp socket !! Well that's one cable that's not gonna' get hot.

Did your joke have a typo in it? Did you mean 1mm? I'm confused.

he meant 10mm2, the cross section area of the cable

 

[Wuffles]

10mm T&E for 16 amp socket !! Well that's one cable that's not gonna' get hot.

Did your joke have a typo in it? Did you mean 1mm? I'm confused.

he meant 10mm2, the cross section area of the cable

My bad, sorry, I missed the word "not". I thought he was suggesting 10mm2 was going to get hot.

 

[PeteG]

10mm T&E for 16 amp socket !! Well that's one cable that's not gonna' get hot.

Okay enough of the mirth from me.

Let me get some things straight.
In the house you have a fairly large consumer unit (CU) with upwards of 8 ways ?? This has 2 RCCD fitted, one looking after some circuits and the other looking after the others. The garage supply comes via a RCCD protected 16 amp MCB, down the Steel Wire Armoured (SWA) "black" cable to the garage CU?
In the garage protected by a 40 amp 30mA RCD, there are 2 circuits. One is lighting fed by a 6 amp MCB the other is "sockets" via a 40 amp MCB.
Why are your sockets protected by a 40 amp breaker, what kind of circuit is it, ring or radial, do you know the cable size?
Would you know the size of the supply cable (SWA) and what is the distance it runs?

I know it's all questions, but we need to know what you have there. There are right ways and wrong ways to achieve your goal, but most of all we need it done the safe way.

Hello n0legs Sorry it's a while to reply, had to move stuff to see the fuse box.

This is the fuse box in house, the garage is on the 16 amp fuse highlighted with a red dot. The black supply cable is in the second image
on the left. The lift chap did say this might need replacing although I did say you have no chance, as it is set in concrete under the
kitchen floor.

Regarding the 40 amp MCB, because the fuse in the house kept tripping when the Dewalt T/S came on, my cousin took
the existing 16 amp one out and popped the 40 in...Made no difference, it still trips!

 

[Adam9453]

i'd be a little concerned about the number of unknowns here.
I would say you need to find out what size the cable is that is supplying the garage consumer unit from the house?
I would say you really need to work out what the draw is from all the machines in your garage and then design the electrical system to supply it.
I'm concerned that you've chosen to use 10mm2 cable from the MCB to the 16amp socket, its massively overkill and leads me to think its not being done by someone that knows what they're doing.
To give you an idea, the cable from my house to my workshop is 10mm2 SWA cable and is supplying the entire workshop not just one socket!!
I think it would be advisable for you to get a qualified electrician round to quote for sorting it properly, explain what you want to achieve and get him to tell you what to buy and how much it will cost to fit it.

 

[Dee J]

Regarding the 40 amp MCB, because the fuse in the house kept tripping when the Dewalt T/S came on, my cousin took
the existing 16 amp one out and popped the 40 in...Made no difference, it still trips!

That's really confusing - so because a trip in the house kept tripping, the trip in the garage was uprated??? I can't follow that logic at all. The trip is the weak link in the chain - so changing any other parameter in the system will not make it any stronger.

 

[PeteG]

I really appreciate all the replies gentlemen, sorry I can't answer many questions, as mentioned I no nothing about electrics.
I've called a qualified electrician who is coming down on Saturday to have a look, and if he has time and there are no major
problems, he might fit it on the spot Shame the Jet didn't turn up as planned, but hopefully all will be OK.

The other thought I had was the home insurance and would it be void if things went pear shaped if the work hadn't been carried
out by someone with the relevant certificates. Turns out the electrics aren't covered on the buildings/home insurance policy anyway,
as a claim would have to be made through the person who carried out the work!

 

[n0legs]

I've called a qualified electrician who is coming down on Saturday to have a look

Hi Pete,
Mate, that's the best course of action for you on this occasion. Not wishing to kick a man when you're down, but as said by others there are a few confusing issues there.
The actual connection/provision of a 16 amp supply is straight forward but there's a few things needing to be put right first. I wouldn't feel confident on advising you on it sorry.
Fairplay though Pete for having the guts to admit you're out of your depth and are calling in a pro =D>
Let us know how it goes.

 

[n0legs]

he meant 10mm2, the cross section area of the cable

My bad, sorry, I missed the word "not". I thought he was suggesting 10mm2 was going to get hot.

:wink:
Was just having a bit of fun

 

[Phil Pascoe]

The smartest thing in all DIY is knowing when to stop.

 

[woodfarmer]

My dad used to say, "If you don't know what you are doing get someone who does"