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?"
There's also insurance reasons as well. Having someone other than a qualified electrician do the work can void your fire insurance.
Suck it up and hire an electrician. Seriously. Yes, those of us who have done lots of electrical work and know not to connect power to ground may feel that it's horribly wrong to pay someone for this, but you really should do it. Even if you know what you're doing, things can always go wrong, and if you're not a licensed electrician you could be opening yourself up to lawsuits by the power company, building code violations, you could lose insurance, etc.
Now, if you want to do your own work inside your house, I would recommend that you get the electrician to install a master lockout switch (different from a master breaker in the panel) between you and the mains supply. Then, play with anything behind that, and you probably won't get in trouble with the power company. You can go re-wire your whole panel yourself, and save some money (getting them to install the lockout switch will be quite cheap comparitively)
There is no sig, there is only Zuul.
Not only is it dangerous and lethal, not to mention analog... its ILLEGAL in most places for you to do the work unless you're a licensed electrician (some exceptions for certain 120vac work). Heck... a lot of places require you to have a Low Voltage certification to run cat5......
For home, who cares,,, for business: follow the rules.
Hire a professional. A real professional. It won't necessarily "be cheap" but it will be safe. When the powers that be balk, ask them which would be "cheaper", getting this fixed and staying operational, or having the whole thing go *POOF* and take the location out of service and still have to get it fixed.
If you are the unlucky person that has to fix it, then find the main that feeds that panel and TURN IT OFF.
Don't even think about trying to fix this problem while it is hot. Not unless you've got a deathwish and, if you have any family you care about, a great big life insurance policy that will still pay out after acts of stupidity.
I've worked around a few power systems, and the one thing above all else, give that electrical panel LOTS OF RESPECT. Always assume a circuit is hot, even if "you KNOW you turned it off earlier". Always leave a flag on the circuit that you turned off so that others know it is off on purpose, especially if you have to turn off a main to kill power to that panel. Always remember SAFETY FIRST, even when your working on a "dead" panel. If you have insulated tools, good -- use them. If you have heavy duty insulated gloves -- use them. Never work alone -- always have somebody around that is aware of what your doing and that can check on you from time to time, or better yet, keep you in sight. They don't have to help you work on the circuits, but if something goes horribly wrong and you get zapped, that person can call 911 and get you help.
. 62,400 repetitions make one truth -- Brave New World, Aldous Huxley
Don't resign. A worker can notify his supervisor that due to what the worker believes that doing the task placed before them will put them in imminent danger, he can refuse to do that task. The worker then needs to fill out a form or two and contact the Occupational Safety & Health Administration. The worker cannot be disciplined for refusing to work in a dangerous situation.
I've felt both a time or two (accidentally). 110 is really more of a tickle and certainly won't kill you.
You've got to be respectful of it but with 110 I didn't even realize I was being shocked until well after the fact.
Dude, 110 volts is most certainly enough to kill. True, most of us have been "tingled" by 110/115 a few times, and didn't die... all that proves is that we were lucky on those occassions.
For an interesting discussion of why low voltages *can* be deadly, see this page.
The bottom line is, lower voltages tend to be "safer" due to the resistance of your body, and the fact that low voltage power sources also usually have a fairly low current capacity. But try wetting your hands and grabbing the leads from an arc welder set on 200+ amps sometime, if you don't think low voltage can f#@k you up.
// TODO: Insert Cool Sig
"First thing to do is SHUT OFF THE POWER AND INSURE IT WILL NOT BE TURNED BACK ON UNTIL YOU ARE DONE!!!"
This is extremely good advice.* Professional electricians will put a little warning sign over any breakers, switches, etc. that are shut off that says essentially, "if you turn on power here, you'll kill someone." Make sure you have one.
That said, I too think this is a very good way to add yourself to the next Darwin Awards.
*Ignoring the goofup with "insure" used rather than "ensure", but that's not a *big* deal.
It's the friggin' *law* in most jurisdictions to get a licensed electrician to do this work, and for very good reason.
In a facility I ran years ago I smelled smoke in our main distribution panel. Called our electrician and he *immediately* turned white, got out of there dragging me with him, closing the door to the small power distribution room behind him and immediately went to the building's main distribution breakers next to the elevator shaft on the bottom floor and turned off all power to our floor.
Why? He'd seen the insulation bubbling on the aluminum power cable that was connected to the main copper bus for the breaker box.
It had been connected without anti-oxidation gel and the aluminum had oxidized increasing resistance to the point where the insulation was near burning.
He told me that an electrician had been killed earlier in the year when a suburban shopping mall's main panel blew up as he was inspecting it, after having been called in during the wee hours of the night by the fire department after a report of smoke had been called in.
If the original poster's company doesn't own the building then the landlord can be forced to pay, just call in the friggin' city electrical inspector and after he shits his pants your building owner will be paying to rewire the box ASAP.
I rewired my whole house from the power pole down (was 40s era ungrounded knob and tube with 30 amp service) so it can be done but some things will make it easier.
First, find an electrician friend or at least an electrician who is DIY friendly and get a professional opinion. If the insulation in the panel is bad it may be bad in the walls as well. You may not want to know.
While you can do the research and learning yourself, a pro will quickly spot certain gotchas like aluminum wiring without the proper anti-corrosion connectors or grease.
They will also likely spot other things you would probably miss such as certain Federal Pacific Electric panels and breakers (http://www.inspect-ny.com/fpe/sec1982.htm).
In my case I knew plenty about electricity in general but hiring a friend for a few hours to review the project and teach me the tricks really helped speed the job. He was also able to review the codes. Again, basic electricity wasn't the problem but my friend was intimate with all the issues like where GFCIs are required, required height of outlets, how many are required per wall, allowed location and hole sizes in floor joists, locations where conduit/BX is and is not required.
A lot of the codes sound arbitrary and to a certain extent they are but before dismissing them as silly remember that they represent the accumulated wisdom from the fires, electrocutions, etc. in the past. Building codes are all written in blood.
A pro can show you good tricks. For example, throw away the stupid paper template that comes with the retrofit junction boxes and simply hold a torpedo level against the box, use a tape to measure the proper height and pencil around the box then cut.
Also, before locating a box take a piece of straight coat-hanger wire, chuck it into a drill, and drill it through the baseboard or ceiling wherever you want to locate the box. Then crawl under the house or into the attic and the wire will give you the exact location so you can check for obstructions and you can drill the holes in the right place. Much better than trying to measure plus coathangers are free and the tiny hole is easily filled with a dab of spackle.
If you do get into major rewiring I recommend a few things:
1. Use 20 amp wiring - the material cost is very slightly higher but labor isn't. You have extra capacity and lower resistance losses.
2. More breakers - OK, I went a bit overboard with well over 20 breakers in a 1200 square foot house but running every kitchen outlet to its own breaker cost me very little in time or money and I have no problem running the microwave, coffee maker, waffle maker, toaster along with the fridge and dishwasher.
3. Outlets everywhere. I added outlets in every closet - they are great for powering chargers, adding a burglar alarm, etc. Add them where you might add appliances - I'm finally getting a garage door opener but the install will be easy since the outlet is already in place. While I was up in the attic I added an outlet under the eaves - handy every Christmas. I increased the number ouf outlets 3-4 fold and have used every one.
4. Run 240 to the garage - you will eventually want to run a small welder and even if not you might want to use it for an illegal backfeed from your generator in a blackout (just be sure to kill the main breaker first).
Upgrading to a solid over-engineered electrical system wasn't like getting a new computer or other toy - it was more like finally getting a pebble out of my shoe (no more blown fuses, no more sticking a three prong adapter on the extension cord then tossing it out the bathroom window to be able to mow the back lawn...) It's work but the result is nice.
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"You are not remembered for doing what is expected of you." - Atul Chitnis
I am a lifelong blue collar guy, gardening, landscaping and construction. I have worked a fair amount part time with electricians. Do it yourself electrical work is ok for outlets, ceiling fans, etc, if you are smart with your hands.
But you need to stay FAR away from the Main Panel unless you are knowledgeable. That thing is dangerous, there ARE many non obvious mistakes you can make if you are not an experienced electrician. You can hurt yourself, burn down the building, damage stuff attached to the electrical system, and if you do something REAL IGNORANT, it is possible (unlikely) you can hurt someone working for the power company outside the house.
This is coming from a Gung Ho!!! Do It Yourselfer/ Shade Tree Mechanic
HenryJamesFeltus.com
Don't have one of those? THAT'S BECAUSE YOU'RE NOT FARKIN' QUALIFIED TO DO THE WORK!
If you have not had the correct training, you CAN NOT safely lock out equipment. Sure. You locked it out. You stuck your wiggy in the wall socket to make sure you got a buzz. You tested each terminal and they were all dead. You started stripping wires. You reached way into the cabinet to unscrew some terminals in the back. It got dark and the building's outside lighting circuit turned on. Guess what? Someone ran the lighting circuit through the box.
oopsie.
You don't know what you're doing. Neither does the person who "told you how" to do this safely. Hire a professional.
"Reality is that which, when you stop believing in it, it doesn't go away." - Philip K. Dick
It's a great idea to call in an inspector periodically. Even the best-wired distribution box will eventually go bad and possibly cause a fire.
Why? Stuff expands when it is heated. Your connections are continually undergoing varying stresses depending on the current. When a connection works itself slightly loose, the resistance increases and the process speeds up.
Where I work, we have the local power service come in and take pictures of our distribution boxes with an infrared camera. That's a great way of pinpointing connections that are heating up too much.
This is the reason a computer can stop working, too...sometimes you can just pop the lid, wiggle everything and cinch it down, and it works.
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Couple of notes from an amateur electrician:
"I would suggest buying several different colors to help keep things straight in the next step."
Um, there are color codes for a reason:
black (for sure), red (if 220), orange (if 3-phase, then it's the high leg) are all hot
white - neutral
no insulation or green - ground
"SHUT OFF THE POWER AND INSURE IT WILL NOT BE TURNED BACK ON UNTIL YOU ARE DONE!!!"
And if possible, pull the meter. Seriously. Have the power company pull the meter, do your work with the meter pulled, then have the power company put the meter back in. However, the power company will probably want to see a permit, and that will take a licensed electrician in most cases, so that may not be an option.
Also...if you are terminating aluminum connections, make sure to use anti-oxidant goop on the terminations and torque them only to the recommended specs. Don't have a torque wrench? Call an electrician. Al is nasty if not terminated correctly. In fact, that goes for all connections. If at possible, beg or borrow a torque wrench so that you can terminate connections to the proper specifications. Note that that only applies to main connections, not branch circuits.
Well, let's see - you can give the current a 1000ohm path from your hand, through your body, and out your foot, or you can give the current a 100 ohm path through your four fingers, palm, thumb and wrist, and lose your hand.
Instead of having a chance at reconstructing a lot of body, you have no hand - it can't be reconstructed at that point. But you won't have to reconstruct your other body parts.
In short, you NEVER, EVER, EVER ground yourself when working on high voltages. IIRC, anything over 60 volts is considered 'high voltage'.
The grounding straps you use for electronics have a built in resistor of 1Meg Ohm or so, but the insulation break down resistance is low, so it will act as a straight route to ground in the presence of high voltage - not good. You only use a certified grounding wire when working with non-powered equipment.
-Adam