automated distribution board

[Beanzy]

The cleaner is a good analogy. If the substance in the spill were a hazardous acid you'd expect to get someone who knew how to sort it out. The hazard in re-setting this MCB is not in resetting it, rather in the proximity to live parts and the lack of protection from contact with those parts.

Lets say the MCB has re-set due to a dead short witin the cabinet you mention. If you just re-set it without taking precautions or just knowing what to look out for, then the copper cable or MCB can explode throwing molten metal out, with whatever injuries resulting. Now this can happen to anyone but someone trained and entering a live cabinet will wear te proper PPE and know what looks out of place or what could be hazardous. I know it seems unlikely, but it needs to be considered or assessed.

Possibly what you need to do is mention this kind of situation to your employer and ask them to get the spark in to give you and some others a run-through in terms of proceedure etc, and maybe buy some Gloves overalls and a mask if you're likely to have to re-set in a live board in future.

An example of how an accident could happen would be when you are reaching in to the board to switch on the breaker, and someone (probably that moaning minnie you mentioned) comes in and drops something or speaks loudly to you. You turn to see and your arm & hand wanders onto a live part as you move. You could loose some fingers that way. I know of a guy in GE in the US did just that.

 

[ban-all-sheds]

my dad left some wires hanging off a wall (pre part p) and turned the circuit back on. I brushed past it and zzzzz for about 3 seconds. 32A ring main. MCB didnt trip.

An MCB is an overcurrent protection device, to get it to trip it requires over 32A which is well above the 0.25A limit which can cause death

That would be why it did cause death, then:

I might electrocute myself . . its happened before

 

[ban-all-sheds]

next i must be fully qualified in using a microwave so i can microwave some chips

If it's at your place of work, yes.

 

[Spark123]

my dad left some wires hanging off a wall (pre part p) and turned the circuit back on. I brushed past it and zzzzz for about 3 seconds. 32A ring main. MCB didnt trip.

An MCB is an overcurrent protection device, to get it to trip it requires over 32A which is well above the 0.25A limit which can cause death

That would be why it did cause death, then:

I might electrocute myself . . its happened before

and crafty is still posting on the forum, eerie or what?

 

[BJS_Spark]

Most decent companies I have worked for have lockable dist. boards to prevent 'non-suitably qualified' persons from going around resetting circuits that may have been isolated for very good reason, along with ones that have tripped. They don't have to be sparks but trained to know what they are doing. An mcb is a circuit protective device after all not just a switch!

 

[Steve]

Most decent companies I have worked for have lockable dist. boards to prevent 'non-suitably qualified' persons from going around resetting circuits that may have been isolated for very good reason, along with ones that have tripped. They don't have to be sparks but trained to know what they are doing. An mcb is a circuit protective device after all not just a switch!

We have a normal 3-phase dist board which is not locked or lockable, so everyone naturally assumes we can resset anything that trips there. All the shops i have worked at have had staff who will reset MCBs when a light blows or anything - untrained etc (I know of one shop where when they turn the lights on in the morning (normal light switches) they also have to reset an MCB as it trips every night or when they turn the lights on)

This automated panel is lockable, and indeed was locked when i found it the other morning, but some bonzo left the key (like a circle with 2 spikes on each side) on top of the cabinet, and i figured if there had been a danger by opening it, the key wouldnt have been left there . . . As it was, i realised there was a danger, but i know where not to put my hands inside - anywhere metallic really. I appreciate the rubbish about liability and all, but really what are the chances of anything going wrong? The C63 would have tripped before any damage had been done i would think (or hope).

And getting electrocuted wasn't pleasant, though i had recovered within the hour and it taught me to be very careful where electrics were concerned. I did have plastic/rubber trainers on, so perhaps this is why i didn't die or anything.

EDIT: i might lock that key in our time delay safe now i've heard all your comments!

 

[HDRW]

...
And getting electrocuted wasn't pleasant

Electrocution is "getting killed by electricity" - I think you're either exaggerating or understating! I think you got an electric shock...

though i had recovered within the hour and it taught me to be very careful where electrics were concerned.

If you had a shock that bad you should really have gone to hospital. Electric shocks can cause damage to the heart which isn't immediately apparent, but can result in heart failure some time (maybe a day or two) later - people have died from this, so please don't dismiss it.

I did have plastic/rubber trainers on, so perhaps this is why i didn't die or anything.

Depends - it's very unlikely that the material is an insulator good enough to save your life. Car tyres are rubber, but they are "vulcanised" which means that carbon is added - the resulting mixture conducts pretty well!

EDIT: i might lock that key in our time delay safe now i've heard all your comments!

Sounds like a good first move - the second would be to seek clarification from your boss(es) as to the procedure to follow in future. Closing the place until the lights are working sounds like a reasonable action to me - if it hits them in the profit they may act to stop it happening again!

Remember that you are responsible for your own H&S - if you do something you know to be dangerous (and you know now!) you may not only get killed, but held responsible for it = no insurance payout...

Cheers,

Howard

 

[johno12345]

where I work, anyone resets any trip that trips, whether it be a RDC, RCBO MCCB or MCB. It is rare that someone calls the electrician over to reset one. I only ever reset the ones in my data centre.

I don't see that it is a good idea resetting things that you don't know all the ins and outs of. In a large place it is quite possible that someone has made contact with a live part so it wouldn't be good resetting breakers willy nilly. I think all places need an appointed person or persons who are aware of what to do when something trips whether it be, get a trician or reset the breaker. there seems to be too much to risk. It also doesn't seem good to be resetting a breaker while the circuit might be faulted. especially on larger amperage breakers.

The dis boards are in a right state here though. The only good thing about the re-wirable boards and the cart fuse boards is that no one can reset them except the trician. so in this case older may be better.

They should be locked to stop the general mass of idiots sticking their fingers in things but this seems to be rarely the case. Unfortunately it will probably take several serious accidents before something is done about it. (sorry to waffle on)

 

[plugwash]

The dis boards are in a right state here though. The only good thing about the re-wirable boards and the cart fuse boards is that no one can reset them except the trician. so in this case older may be better.

hairpins?
tinfoil?

are you sure such boards are really a good thing, at least with a mcb board its bloody awkward to bypass the protection.

 

[olly_k]

across the contacts - 12v , between a contact and ground - it depends where on the string it was, anything between 0v and 240v is possible, current will be whatever current the volatage is able to push through you, which depends on conditions

Maybe knit picking here (don't normally say a lot) surely there will be a minimum voltage hazard, because you are acting as a potential didvider...?
assuming 60mA bulbs x20 and approx 2k body impedance, I get a minimum 80V shock hazard, unless I guess you are lucky enough to touch the neutral side on the last bulb correct me if wrong!