Electrical safety

[SparkyBaws]

Hi all, I am currently doing an electrical presentation on labeling of an electrical install. I want to add a safety moment on as to why we label cables, panels, equipment and so on. I am having a slight mental block at the moment though, does anyone have any input or ideas they could share from their experiences?

Thanks.

[jim dungar]

Labels let workers know what hazards may exist and what preventative measured, like PPE, may be required.

[Hv&Lv]

Hi all, I am currently doing an electrical presentation on labeling of an electrical install. I want to add a safety moment on as to why we label cables, panels, equipment and so on. I am having a slight mental block at the moment though, does anyone have any input or ideas they could share from their experiences?

Thanks.

Safety moment here...
We have an old 1500kVA padmount transformer that feeds one motor only at a chipper plant.
its been there for 30+ years.
no labeling on the outside or inside other than the data plate, and we all know the data plate is placed above the X bushings on the back wall...
one day the plant calls, the chipper is down.
Trouble crew goes out there, tries to check voltage.
meter blows up in his hand... luckily he wasn’t hurt. Pride only...
the transformer was a 25 kV/ 4160. The meter was rated to 1000V.
turns out their switch inside had a contractor burnt out. Wouldn’t close...
labels everywhere now, inside and outside. All our transformers have the voltage clearly labeled on them. Now...

[PaulMmn]

Used to be there was always an 'old guy' who worked everywhere, who knew all of the machinery, and the switches, and could tell the new guys all about it.

Now, he's retired to Florida, and all the new guys have moved on to more financially lucrative jobs elsewhere. And all those stories the 'old guy' told have gone with them.

That's why we need labels and cautions on everything. Because there aren't any 'old guys' to tell you what's what.

Has anyone ever heard of whirling through your place of work and "5S"ing it? Stands for Sort, Set in order, Shine, Standardize, and Sustain. Even though someone in this country wrote about the principles, Japan was the country that took those lessons to heart-- label everything, organize everything. Now we're realizing those are good ideas!

5S:
Sort - Basic idea is that you go through everything and throw out all those things you've been meaning to;
Set in Order - organize your workplace-- "a place for everything and everything in its place--" including labeling positions on the tool rack, making a tape border on the floor for 'do not park stuff here,' etc.;
Shine - Take care of housekeeping- don't let the dust bunnies turn into gorillas;
Standardize - perform the same job the same way all the time
Sustain - Don't let things get disorganized again!

The first S is Sort-- which includes trashing what should be trashed. I added a caveat where I work-- it's not junk until I say it's junk! I think I'm the 'old guy.' When someone can't identify something, the tendency is to call it junk and toss it. In many cases, I can tell them what the part came from, and why it's not junk.

There's also a tendency to toss out old manuals for equipment! I believe that if we have a piece of equipment, anywhere in the company, we don't toss out the manual! Sometimes even The Internet doesn't have a copy of the manual!

[PaulMmn]

Safety moment here...
...turns out their switch inside had a contractor burnt out. Wouldn’t close...

Sometimes contractors do burn out!

[Hv&Lv]

Sometimes contractors do burn out!

Whoops...
Hey, turns out someone does read my posts..

[SparkyBaws]

Thanks for the replies. I've went for 'test before you touch' although I want to speak about the positives of labeling and why it's a must, it is also important to not fully rely on it. The 5xS's haha I quite like that.

[zog]

Thanks for the replies. I've went for 'test before you touch' although I want to speak about the positives of labeling and why it's a must, it is also important to not fully rely on it. The 5xS's haha I quite like that.

These days it is suit up before you test before you touch, only way to know what arc flash PPE you need to wear is from the label

[ATSman]

Too bad this gent didn't read this post before working:

https://www.liveleak.com/view?t=slntS_1573385668 copy & paste

Doesn't look like his PPE was rated for the available fault current at those fused switches. Line side short, maybe?

[powerpete69]

Hi all, I am currently doing an electrical presentation on labeling of an electrical install. I want to add a safety moment on as to why we label cables, panels, equipment and so on. I am having a slight mental block at the moment though, does anyone have any input or ideas they could share from their experiences?

Thanks.

Arc flash labels are typically the most important labels. To obtain these one would need to use some of the programs available, EasyPower, SKM or Etap. You would have to build the correct electrical model to simulate your real situation in one of these programs. Arc flash labels tell the amount of energy available in an energized panel. They tell the amount of calories per cm squared that would be released in an arc flash incident. (short circuiting all three phases) We always try to de-energize panels before working on them but there are some exceptions where this is not possible. Arc flash labels also tell the proper PPE equipment that would be need to safely do the work.

These programs will also simulate the maximum short circuit current which would allow you to select the correct short circuit for your panel. Panels typically come in 10kA, 18kA, 22kA, 35kA, 42ka, 65kA and 100kA. The higher the rating, the more costly the panel. However if not rated high enough, the breaker will fail when you need it most and or the bus bars will tear off the panel due to the massive magnetic force. You can also take the ultra conservative approach of infinite bus. You calculate the full load amps of the secondary of the transformer feeding your panel. You then divide by its impedance, this gives max short circuit amps. You can never go wrong with this as far as field application (other than making too stout a system in regards to money), but short circuit current drops as it goes thru breakers, fuses and smaller wires. Typically do both calcs and then make a sound decision from there.

Other labels on an electrical panel would simply state the voltage, amperage, three phase or single phase, MLO or MCB, things like that.