Slashdot Mirror
Solving a Wiring Mess?
FueledByRamen asks: "While trying to run a new power line for a large Sun mass-storage cabinet (located nowhere near a 220 outlet of course), I had the misfortune of needing to pop the lid on my main power distribution panel (previously opened in the late 80s). The whole thing is a rats nest and probably a fire hazard - old-style wiring with broken-down cloth/plastic insulation strewn everywhere, and the utility's incoming power cables have some sort of junction in them that's the size of a 1-liter bottle (on each wire) and is covered in layers of electrical tape. Even (gently) putting the panel back on jiggled something important, and there was a nasty cracking noise and half the breakers blew (all breakers in one of the 2 columns). I've worked with mains voltage in the past (wiring new rooms, installing lighting), but nothing on this scale, both in terms of complexity and potential for death. How do you industrious Slashdot readers go about fixing a mess like this (on a tight budget, no less) without getting a mains-induced glimpse at the great beyond?"
send an email to your PHB that says things like "fire hazard" "risk to operations" "danger to employees and $$$$ equiment" "violation of code" and/or "insurance risk". That should get you the authorization you need to do whatever needs to be done - which, as others have pointed out, is HIRE A PROFESSIONAL.
Is the juice worth the sqeeze?
How do you industrious Slashdot readers go about fixing a mess like this (on a tight budget, no less) without getting a mains-induced glimpse at the great beyond?
There's two obvious answers here:
1. Hire an electrician.
2. If you're going to mess with it yourself, unplug it first. 220V AC isn't a problem when you've got a three-foot airgap.
Tarsnap: Online backups for the truly paranoid
... at least through extremities. My old high school physics teacher used to stick his finger in light sockets for laughs. Then he would pull out the Variac and let you stick your own finger in a light socket with variable AC voltage. Up to about 30 VDC you couldn't feel a thing. When you control the voltage yourself, 110VAC is no big deal at all -- just a strong tingling in the finger (in the light socket).
How 'bout putting up a picture of that mess for us to enjoy?
If the answer to that is NO, then STOP WHAT YOU ARE DOING AND CALL THE BUILDING OWNER, inform him of the sub-standard wiring you found and ask him how you can 'work together' to get it fixed without any inconvienience, like reporting it :)
If your company owns the building, GET PROFESSIONAL HELP 220/440 is not for playing with, and any micro variations WILL cause problems in the future. Our MTF (money transfer faciclity) had a single strand not properly grounded in a secure vault, and everytime then bloody door was slammed it caused a parity error on a mulitprocessing enviroment and forced several hundred transactions to be re-run. Took 2 or 3 weeks and power monitors to locate the short and LOTS OF TIME to correct, minimize it by using people WHO KNOW WHAT THEY ARE DOING.
errr....umm...*whooosh* *whoosh* Is this thing on ?
I used to write software at a high-energy physics lab. The technicians would put padlocks that only they had keys for on switches when they powered something down. Removing someone else's lock was grounds for immediate dismissal. If someone accidentally left a lock on something, they had to personally remove it or (you guessed it) face dismissal. They took these rules very seriously.
1. Buy/setup new power system
2. Move systems over one by one
3. Repeat as needed
4. Disconnect old system from power all at once
5. Trash bins out back
6. Proffitt??
#6495ED - cornflower blue
fixed a fuse with tinfoil
I've done that -- not a house fuse, but the "slow-blow" fuse protecting the motor in a (now ancient) Decwriter dot matrix terminal. (As I said, ancient technology). It was late, I was fixing some code, and a piece of paper jammed the print head and the fuse blew. No spare fuses. So I got a foil-wrapped chocolate bar out of the vending machine, wrapped some foil around the burnt-out fuse, replaced it and kept coding.
And yes, left a note to remind myself or whoever used the terminal next to replace it with a proper fuse.
-- Alastair
Actually, wouldn't it make sense to wear a metal bracelet with a thick gauge copper wire wired directly to ground? Then if current happened to flow into your hand it would preferentially flow straight to ground through the copper path, instead of through your body.
Not that I'm advocating working on a high voltage setup, I'm simply asking out of curiosity...
When I wire something for myself, it might not be perfect, but with the help of an experienced electrician, it will be good enough to be safe, legal, reliable, and simple to expand from. When an unscrupulous professional wires something, it will be done just well enough to fool the inspectors.
Information wants to be anthropomorphized.
At Brookhaven National Lab, the high-voltage systems are considered relatively safe. It's the 5V electronics-power distribution systems that carry upwards of 600A and have fuses bigger around than your fist. Shorting one of those with a wrench would make the wrench explode.
110V can tickle. 5V can kill.
it's not the volts it's the amps that getcha
God, I knew someone was going to say that. Ohm's law... I=V/R. If the voltage goes up, so does the current. They are not mutually exclusive.
Yoda of Borg am I! Assimilated shall you be! Futile resistance is, hmm?
I think that everyone here is pretty much saying the same thing: "IT IS STUPID TO TRY TO DO THIS YOURSELF!"
I have been on the recieving end of a 220v shock because someone flipped a breaker on a circuit after someone else did a home-brew wiring job. Had I picked up the wire with two hands rather than one, I would be dead and decomposing nicely by now.
I have done my fair share of homebrew jobs and after a number of lessons learned the hard way. I now have a lot of respect for electricity and use a great deal of caution with any wiring job.
Wiring something from scratch is one thing, what you describe is a DEATH TRAP!!! DON'T EVEN THINK ABOUT IT!!
I suspect that even an experienced professional would be a bit gun-shy with the setup that you have.
[And yes, I have replaced contact swtiches in my microwave, serviced the non user-servicable parts in my TV, swapped parts in my computer's power supply, re-wired my car, and a lot of other dumb things. I have some idea of what I am doing, but I wouldn't even consider doing that wiring job for a nano-second! Even I am not that deranged.]
> Maybe they do where you live, but here, you hang a lock.
mod parent up - this is the best advice.
A couple years ago I had someone "helpfully" turn on some breakers they thought were blown... while I was digging in a downstream electrical box. AC in one hand, out the knee on the same side. If I had been kneeling on the opposite knee it would have crossed more of my internal organs and quite possibly could have been fatal. Instead I escaped with just some minor burns and a hell of a jolt. God, just thinking about it hurts.
After that I started padlocking the upstream breaker box... and tying the only key to my bootlace.
Thankfully I don't have to do much electrical work anymore.
> Hire a professional.
Definately. Anything as bad as what is described should NEVER be touched by an amateur. It's way too easy to fuck up and hurt yourself very badly.
Some places require locks and tags to be sure the power doesn't accidently get turned back on while you're working.
:) Luckly, I didn't even work in a department that did physical repairs. We were just warned so some idiot wouldn't turn on a conveyor (or whatever) that was intentionally shut down.
I spent some time at a Walmart warehouse. Big facility, lots of cool conveyor belts. They made a *HUGE* point of tagging and locking anything you're working on. I guess it only makes it slightly more hazardous that all their racks are metal, so if you have a main wire disconnected, and it was touching the metal of the racks, you could make an electrical hazard out of a piece of metal 3 stories high and a couple hundred feet long.
Serious? Seriousness is well above my pay grade.
If you're talking about not having a 220-volt outlet nearby, you're probably American. But you're calling it "mains power", which is usually a Commonwealth thing. Are you by chance Canadian?
In most of the US, at least if you're in a city or a medium-heavily-populated county, there's probably a building code electrical code that says who's allowed to work on what kind of electricity. Usually in a home, you're allowed to work on sockets and switches inside existing electrical boxes, and almost everywhere you're not allowed to touch the main power feed yourself, and in some jurisdictions you can install new electrical boxes and plug-in circuit breakers yourself and in some you can't. (In New Jersey, you can negotiate with the building inspectors about not noticing things, but Darwin usually wants bigger bribes than they do...) In commercial buildings, you're more likely to need a license.
If you're required to use a licensed electrician for something, and you do it yourself, various Bad Things can happen, and if you do it your self and something goes wrong, more Bad Things _will_ happen. You do not want this... And you said that it looked ugly in there - this significantly increases the chances that if you do work on it yourself, something will go wrong, or perhaps Terribly Wrong, either because it really is an ugly mess or because it's beyond your skill level or both. And if you're renting your building instead of owning it yourself, your lease probably mentions some of the requirements. If you have fire insurance or liability insurance, those contracts probably also require licensed electricians for cases like this.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
This one is way more advanced. Just be careful where you point it.
Interesting, this is essentially how public key encryption works.
The problem they're trying to solve is that a message gets sent through a public channel (such as the postal service) without either party giving up their private key and without the data ever being unencrypted until it's safely in the hands of the recipient. The best explanation of it I've heard goes like this.
"Alice writes a message and locks it in a chest with her padlock. This chest has holes (hasps) for two separate padlocks. [Note: no reason it can't have n hasps, as in the wiring example.] She sends the locked box to Bob through the mail.
Bob places his own padlock through the remaining hasp, and mails it back to Alice.
Alice removes her own padlock and mails the box, with just Bob's padlock on it, back to Bob.
Bob removes his own padlock and reads the message."
Of course, this is all being done over TCP instead of the post, and with math instead of padlocks, but you get the idea.
None of this has anything to do with a wiring mess, but the similarities are striking.
It's rare that you're presented with a knob whose only two positions are Make History and Flee Your Glorious Destiny.
I did some theater work, in the totally amateur area, and on one production that I produced, I had to wire the lighting panel into the mains, because the theater was built in 1924 and still had most of its original lighting equipment. We figured that 75-year old rheostat dimmers the size of car tires that made a sound like a chainsaw when you pulled the foot-long lever weren't going to work well for our production.
So we borrowed/rented the equipment we needed, and the lights, wired everything up, and got ready to hook the main control box up. I got the pigtails ready and opened up the panel where the theater tech told me the power should be.
Inside, three very large, uninsulated, copper bars going from top to bottom.
All the others with me just looked at it and said "all yours, man". Great. So I double-checked the power was turned off to this panel- it had a very large switch, and you could *see* the switches disengage, but I still didn't trust that, then triple-checked it with a meter.
I was still nervous as all hell just putting my hand near these things, even knowing they were off. One handed, keeping the other hand behind me (I remembered that advice from my HS electronics teacher) I undid the big allen bolts and hooked the pigtail up.
It actually worked first try. Undoing it at the end of the production was almost as harrowing as the first time. I had the old mantra of labratory physics running through my head- "Hot glass looks exactly like cold glass", only I had modified it to "live copper looks exactly like dead copper". I also knew that if it was live, I probably wouldn't even know it before I was killed or rendered unconscious.
Yeesh. I still can't believe I was stupid or bold enough to do that.
In keeping with the other folks here, I'd say to the original asker, hire a bloody electrician, and don't get near the thing until someone tells you it's safe. Budget be damned, you don't want to risk your life on something like that.
Hooking up a simple pigtail is one thing, futzing around in the panel you described is suicide.
On a side note, I once got nailed by a 220 V dryer when I was about 8 years old. I was reaching for a sock that had fallen behind it, and touched one of the leads that was left exposed (!). It threw me about 15 feet across the laundry room and put a crack in the door where I hit it.
Ohhhh, puh-lease! This is electricity, it ain't friggin' magic!
I personally rewired my entire house, replacing the main fuse-box and all of the knob and tube wiring in the house. Most of the the patch-work in the house (probably done by "licensed" electricians) was shit that I couldn't have done that badly half-drunk. It was terrible.
My community requires inspection after work is done and all of my work was code or better. I am an electrical engineer and most of the electrical code seemed like common-sense to me. Recall, this is my house; if I didn't think the job was right (with or without an inspection), I certainly wouldn't be living here.
BTW, the code relaxation that allowed aluminum to copper compression connections (horror story elsewhere in this thread) was a short-lived aberration (at least here in te Midwest) and that is something that would probably have to be replaced after an inspection whether it showed problems or not!
Yep, in your home too. My late 1960's home w/100amp breaker/distribution box had warm connections when running heavy (cook stove) loads. A simple tighten down of connections; cool at full load.
I worked down at Kennedy Space Center, in the old Flight Crew Training building. It had a crawlspace that was used to run wires, which was accessible by pulling up one of the big, heavy floor tiles (there was a special tile-pulling tool). The crawlspace was maybe three feet deep -- with the bottom foot or so consisting of old cables, dating back to the Apollo days. Pulling up a floor tile always reminded me of the scene in Raiders of the Lost Ark -- all that was missing was a dropped torch and Indy saying "Snakes... Why did it have to be snakes?" Anyway, every time they tried to clean out these wires, they ended up knocking out something important, so eventually they just let them accumulate.
One time we had to run a network cable from one end of the building to the other -- nearly 100 meters -- and the only way we could figure out to do it was to send someone down there to crawl it through. I'm glad I didn't draw the short straw that day...
I object to that article, and to the next reply.
There are way, way too many variables at work here for you to even think about doing this yourself.
...but you will be the one on trial for manslaughter. Or criminal damage. You will plea bargain, successfully. You'll have a minor criminal record, and will only have a minimum of jail time - possibly only community service. If you're lucky, you'll only have to see the family of the dead fire victim once, at sentencing.... ...all because back in 2003 you decided that your employer would most likely be pissed with a $5000 bill for electrical work.
Here's a situation - quite likely, actually, happens all the time:
You "fix" it. Somehow. By some miracle. You don't even seem to break anything.
Two years from now, the "Super-Duper Electrical Bonding Compound Series A-723A-P" that you used cannot handle the heat surge. There is a fire. There are several hundred thousand dollars worth of damage, or worse, a person dies.
A full investigation ensues. It is found that some idiot used Super-Duper Electrical Bonding Compound Series A-723A-P to join two wires when, of course, any competent licensed electrician knows perfectly well that since there is a Purple Snoklefactor drawing 23.3 amps off of main bus B, the specs call for Compound A-723-A-PqA-7! You idiot!
The investigators realize that only a talented layman who doesn't do it for a living would have made such a simple mistake. Armed with supeanea power, they swoop in, asking anyone and everyone "Have you ever seen anyone in that box?" Your company, is a desperate attempt to avoid being sued for MILLIONS - I am not exaggerating - of dollars, decides to finger you as the person who made unauthorized repairs, in an attempt to shift at least part of the liability on you. It won't suceed, of course, they will still have to pay something...
Is it really worth it? This type of stuff happens all the time. Electricity is simple, at heart - but the complex interactions that go on in the heart of commercial power should only be tampered with by those who know EXACTLY what they are doing. Otherwise, buildings burn, property is lost, and people die.
I know the type. Fifty years ago, he would have been one of those guys that had a fuse blow, and since he didn't have a fuse on hand, stuck a penny in the fuse socket "just until the hardware store opens up on Monday," i.e., until someone buys the house thirty years later.
My brother-in-law bought a nice, old house in a small town a few years ago, for a really reasonable price. It was owned by an appliance dealer, who...ahem...did all his own wiring.... (You can tell by the background music where the monster is hiding, can't you?)
$15,000 later, it probably won't burn down from electrical causes.
With the latter solution, if it hasn't rained for a while, then the ground is too dry and it doesn't drain the power and so flip the MCB (or blow the fuse). With the former solution, bits of corrosion can reduce the conductivity between wire and pipe and they cease to work correctly too.
The modern way of doing it is to stick a diode-based system on the neutral wire (behind the meter) that returns to the power station and attach the ground/earth wires to that. This ensures that any electricity that floods through ground goes straight back to the power station, and that the returning circuit current cannot instead go to earth and flood through someone/something that is touching an earthed item.
Now, even the more modern method relies on a component that could break and you wouldn't know it had broken until too late. This is why plastic is good. The best defense against wires touching the plastic covering and so slowly melting it, is to have a fuse of appropriate size in your plug. Wires only melt when too much current is going through them. If you have a fuse rated lower than the maximum current for all the wires in the device then that will blow before a wire catches fire. All UK plugs have fuses in them (although lazy people often just stick 13 amp fuses in them - even if it is only a lamp). Do US plugs have the same?