Close call today...

This morning I went out to a jobsite to make a minor program change. As a matter of practice we install a duplex receptical in the controller encloser for use with the laptops. On this particular job the receptical is located on the left side of the enclosure..facing the controller transforms (about 10" away). So when I'm done, I pull the plug and the back of my right hand makes contact with the 480v transformer primary.... As luck would have it I just happen not to have been touching ANYthing else when this happened, but I was still knocked silly...

All is well...(still a little shaken, and sore), but I thought I'd mention it.

BE ALERT!!! Safety is no accident..and it can happen to YOU!!

It's good to hear you're OK, Mike. It's never any fun when stuff like this happens.

You're right. We work with potentially dangerous stuff every day. And bad things happen REAL fast.

Keith

A goood warning for all. Glad you are able to tell us about it.

I had a panel inspected and had put black tape over the terminals, and got an ataboy. I think a clear cellophane packing tape may be a slightly better idea.

No, doubt, somebody will have a good solution.

Thin plexiglas is fine, but it can get expensive and time consuming to cover everything.

As I said, "Glad you are able to tell us about it".

bestest regards.....casey

Mike
thanks god you are OK.

Thin plexiglas is fine

Click to expand...

We usually use it in our panels to cover the hazerdous parts in the panel,it's also gives a good view in the panel

It's a fine thing you are ok Mike.

This incident has me thinking about the relative contrast between the North American approach which emphasises door interlocks to prevent access but allows exposed live terminals once inside, and the European practise which seems to be less concerned with restricting access, but much hotter on "finger safe" when the door is open.

Coming from New Zealand we follow the European IEC standards mostly, so I am wondering if my impression of the NEC code is correct? Or to what extent has "finger safe" penetrated North America in recent years?

But all discussion of electrical standards aside, there is always the potential for something like this to happen regardless and it there is no harm in being reminded about it from time to time ...after all the definition of an accident is something you didn't expect. Have you bought your Lotto tickets yet Mike?

"Dr." Mike, then "Special" Mike, now "Lucky" Mike!...

PhilipW said:

...to what extent has "finger safe" penetrated North America in recent years?

Click to expand...

Sadly, very little. At least the stuff I've seen. I still see plenty of open style fuseholders, exposed terminal control transformers, which, by the way, you CAN buy finger-safe covers for (and they're CHEAP!), yet no one does...

Oh, and those damned Square-D terminal blocks that Grainger sells!...

I, for one, have not built a panel in the last 10 years that was not 100% finger-safe. It's really not very difficult or expensive, so there's no reason why NOT to.



-Eric

The only problem I have seen with the finger safe is it is a little harder to see if you have a bad / getting hot connector in the component. They are also a little harder to clean up. Other wise I think they are pretty good.

Dan Bentler

Oh yes. Good thing you came thru it OK Mike.

Dan Bentler

It is good you are OK . It is interesting that people waffle on about "CODE" , but you're are allowed to build panels where this can happen by accident ( agreed the dedicate loon can hurt themselves whatever) but to have unshielded phase cables floating around is just cheap and terrible . My life has a value much in excess of any job . I find that when panel builders or electricians or whoever cause such a situation that grapping them firmly by the forearm and pushing their hand towards the danger point soon creates a change in attitude .
I don't know whether you panel was using the odd grounded leg system that happens in the US , where phase conductors can be at 480 or so volts relative to ground - if not , thankfully the 480V only passed through your hand , 480 V through the old jam tart ( hand through body to earth- or worse hand through hand to earth) would be pretty close to fatal for many people . Still the belt is not nice , and you are lucky you didn't burn your hand .

Don't be afraid to may a stink about dangerous conditions , even if they do comply with "code" - next time you - or anyone may not be so lucky .

That is one bad experience there, Mike. I had one too only it's a 380V much smaller, but still its dangerous.
I believe at least a shielding (a covering) over the transformer, make of maybe plastic, to just prevent people from being stung. It's a terribly bad numb!

Hope you are feeling alright, mike. take care~

regards
Sherine T.

I worked on a panel that had a 240V ac lamp in the panel door with bare terminals.
The door closed while I was in there and touched my bare arm ?@**?/@@ that makes you jump a bit

Mike,

You need to try one of these:
http://www.grace-eng.com/ge/index.html


In a "hot" panel without your PPE?

Take a look at NFPA 70E!!!

Glad you are OK Mike, 480V can make your eyes water.

Here is an extract from my MCC construction handbook;

7.4.1 Protection against direct contact



The following methods will be used to ensure protection from direct contact with live parts;



a. Use completely insulated components, cables busbars, actuators etc.

b. All enclosures are to be at least IP2X see 7.2. If the enclosure is non-insulated then the minimum creepage distance of 8mm is to be observed

c. All enclosure barriers, lids doors etc. are to have durable fixing arrangements that allow for removal and replacement in-service

d. All compartment doors that give access to dangerous voltages will be fitted with interlocked isolators. Or a physical barrier will be placed between the live parts and the opening that can only be removed by a tool where an interlocked isolator is not practical. Compartments do not need to have an interlocked door if all the terminals and connectors inside are at least IP2X. All form 1 enclosures will be fitted with a door-interlocked disconnector.

e. The location of lamp holders, fuses and similar devices will be positioned to prevent accidental contact with live parts or mounted in a separate compartment.


Generally I use IP2X (finger-safe) components anyway as at some point in time some-one will have to work on it live , the above is to meet the requirements of the European Low Voltage Directive. It is not that easy to get components that a AREN'T IP2X in Europe now.

Having said all that, plenty of people in Europe still manage to electricute themselves.

My "favorite" was in the dim and distant past when I used to have to do domestic work , leaning accros the top of a copper hot water cylinder to take the cap off an immersion heater to find that :-
a) the cap was off
b) the isolator was bypassed

That does make you stand up .

I am afraid that my capability to work on live services is disappearing fast -
I used to do 11KV work - mostly live , where you don't make many mistakes , and thought nothing of cutting JB's in to live 240V services , but now , the old fingers are getting soft on the laptop keyboard.

This reminds me of when I worked for a previous company, I won't name them, I had to add some extra circuits to some panels. I opened one of the panels up and found there to be no means of isolating the part of the circuit I needed to work on, the 3 phase busbars were also exposed and dangerously close to where I would be working. I told the managing director who happened to be standing nearby that I wanted to shut the power off on the main incomer to fit purpex covers over the busbars and to fit an MCCB to enable this panel to be isolated so as to make it safe for future work that will need to be carried out.

The managing director's reply was.. "You can't shut the power off, that will halt production! It's been like this for years, other people have worked on it live so you can!"

I then grabbed his hand and went to grabbed hold of a busbar, at the same time saying "If I'm gonna get an electric shock then so are you!!!" The managing director promptly 'shi*' himself and hurried away muttering something about 'bloddy electricians'.

I left that company as soon as I could.

Just for the record I got my own way and the power was shut off while I carried out the modifications. Also, due to the MD's attitude to my safety I dragged the job out and had the power shut off for 4 hours instead of 1 at the most!

Paul