I got a shock today...

[Skint Eastwood]

...when I was poking around in the spaghetti of my mate's CU. My little finger happened to brush across the two screws holding the incoming cables above the main switch (see photo).

Just wondering why this happened. Shouldn't there be some sort of protection against accidentally touching live parts like that, even in a CU?

I imagine its unlikely there would be much difference between the voltage of the incoming cables, therefore not much danger. But what if there was a more significant imbalance? Couldn't that be lethal?

Surprises me that its so easy to do something like that. Maybe I should just be more careful.

 

[mogga]

there would probably have been a cover at somepoint but it has become lost/thrownaway in the passing of time but why "poke about" when by the picture it is clearly visable ??

BTW id get that cu changed asap by a qualified bod

 

[acat]

Be more careful or get your brother Clint to have a shoot out

Chris

 

[rocker]

Maybe I should just be more careful.

THIS!

Nowadays you'd get some kind of plastic covering over those screws, but depending on who installed it, it's not always going to be there. There are also plenty of places inside a consumer unit which can shock you. Under the right conditions (which can be achieved very easily) a shock from this will be fatal. as little as 30mA across your heart can kill you, that is a tiny amount, about 10 times less than a mobile phone charger. If you don't know what you're doing, do not attempt this sort of thing. If you do know what you're doing, take a lot more care!

 

[Des 56]

There is a cover that was supposed to be over the terminals
They are not onsidered dangerous because you need the use of a tool to get to them(the consumer unit cover)
However they are very dangerous to touch
It is lucky you didn't touch earth at he same time

Be a lot more careful when dealing with a live installation
Isolate where possible and test that it is dead before touching or getting hands inside
You seem to have been lucky on this occasion
Best to be sure of things before investigating

 

[Skint Eastwood]

Well I wasn't 'poking about' just for fun. I think I was trying to move the incomers out of the way a bit so I could identify and remove the ring cables. I'm not the most experienced, but I've soon learned that lesson, to stay away from those screws!

Its a pretty crap CU I know, but my mate won't be interested in changing it. Its way low down in a tiny space at the bottom of a cupboard too, nightmare to work on.

 

[Spa Key]

Well I wasn't 'poking about' just for fun. I think I was trying to move the incomers out of the way a bit so I could identify and remove the ring cables. I'm not the most experienced, but I've soon learned that lesson, to stay away from those screws!

Its a pretty crap CU I know, but my mate won't be interested in changing it. Its way low down in a tiny space at the bottom of a cupboard too, nightmare to work on.

If you're fiddling about in a live installation don't use your fingers. Shift things about with insulated tools, that's what they're designed for.

 

[davelerave]

the first 'barrier' to 'direct contact' is the cover - the modern breakers are IP2X i think

so you can poke about safely


old electrical stuff is brutal for 'direct contact' protection

 

[johnboy6083]

if your not qualified, then dont work on anything live at all! even qualified electricians can only work live where it is not reasonably practical to isolate the installation. this is not one of these instances

 

[Skint Eastwood]

...If you don't know what you're doing, do not attempt this sort of thing. If you do know what you're doing, take a lot more care!

Well I know what I was doing, I'm just not too sure of what NOT to do sometimes. I guess working on any kind of electrical installation you can't EXPECT everything to be sound and safe as per regs. You have to err on the side of caution, and assume that there IS something dangerous lurking there. Like driving, you should expect some idiot to pull out in front of you at any time.

I am aware that a very small current can be lethal. Its early days for me as a budding sparky, maybe I'm lucky it didn't come to a very sudden end!

 

[Skint Eastwood]

if your not qualified, then dont work on anything live at all! even qualified electricians can only work live where it is not reasonably practical to isolate the installation. this is not one of these instances

May be a stupid question, but how would I isolate those incoming cables in this instance? I wasn't "working live", I was just doing a continuity test. (I have C&G 2330/3, but they didn't teach me common sense!)

...Shift things about with insulated tools...

Will do. Lesson learned!

 

[rocker]

May be a stupid question, but how would I isolate those incoming cables in this instance? I wasn't "working live", I was just doing a continuity test. (I have C&G 2330/3, but they didn't teach me common sense!)

Well you *could* pull the fuse, but as a law abiding citizen you'd *never* do such a thing.

Lesson one: always expect everything to be wrong. Because 90% of the time,it is. And no, I'm not exaggerating. Welcome to the wonderful world of domestic installation.

 

[Phil]

May be a stupid question, but how would I isolate those incoming cables in this instance? I wasn't "working live", I was just doing a continuity test. (I have C&G 2330/3, but they didn't teach me common sense!)

part of the 2330 should have been safe isolation and a question in your exam on it. the way of isolating would be to get the dno to install an dp isolator


Will do. Lesson learned!

thats what experience is for hopefully your still here after the mistakes we make

 

[Spa Key]

May be a stupid question, but how would I isolate those incoming cables in this instance? I wasn't "working live", I was just doing a continuity test. (I have C&G 2330/3, but they didn't teach me common sense!)




Will do. Lesson learned!

I don't want to sound patronising, but how on earth did you sit there for 3 years, listen to your tutors go on and on about isolation/insulation, and then open up that CU and fail to think 'they're live'?

Out of curiosity, is that 16mm T+E in the top of the isolator? Where does that go?

 

[Spudnik]

Looking at the supply T&E i would say its is supplied Via a submain somewhere in the building.

 

[davelerave]

so is that a TT board then?? sorry i dont work in UK


looks like a supply for a shower maybe looped off??

 

[Skint Eastwood]

...part of the 2330 should have been safe isolation and a question in your exam on it. the way of isolating would be to get the dno to install an dp isolator...

But would anybody actually do that, prior to a simple test and inspection? I doubt it, but I appreciate your thoughts.

In my experience the 2330 is sorely lacking in many areas, not least in preparation for what will be encountered in the real world. This forum helps fill a lot of those blanks.

I remember safe isolation as in the procedure to be gone through before working on a circuit, ie locking off etc. I know nothing about DP Isolators or main fuses.

 

[nickblake]

its only 50 ma which could be fatal , always class even a dead circuit as live. if your poking around in a live board not recommended as you have found out , put one hand in your pocket ,this way if you do get a shock it will not travel right accross your heart and possible blow your hand away ,litttle story i was working on a over sink water heater took fuse out switched it off tested supply ,changed the thermostat , put fuse in switched on live tested it all ok ,switched off went to put cover back on stat wasnt quite in position so i grabbed the stat not realising id caught the switch with the cover my arm hit the sink like metal to a magnet next i remeber is i was on the other side of the room with one aching arm ,still alive though since that day ive always checked and double checked you may not have that 2nd chance treat with respect as you cant see if its live

 

[Phil]

tbh the 2330 does lack a lot to do with the real world. but before sticking fingers inside a board you have to look carefully and identify the risks, a previous post this week said "it bites and it bites hard" yeh that`s one to remember. not many people arrange for the dno to provide a means of isolation before any works i was just saying how the board could be isolated rather than pulling the fuse. don`t take most of the replies as a criticism just take on board the thoughts and if you are not ready to go inside boards with live parts wait till you gain more experience with a good spark that can show you the side of the job the college can`t or didn`t show you.

 

[rocker]

its only 50 ma which could be fatal

If you are a healthy 25 year old with no unknown congenital heart probem. The fact is that the little belt this guy had could have put his heart out of sync, and he could drop dead in a weeks time. Improbable, but not impossible.

put one hand in your pocket

This MAY help you as an absolute last line of defence. Do not rely on it.

EDIT: Sorry Nick, just re-read and realised your post wasn't a response to mine. The point still stands, though!