Got a shock.

[diracshore]

Currently I live in a old Victorian house. Seems to have no ground in the wiring. I was changing a light bulb and I got a shock for about a second from the bulb. Now the light switch was off, so I am surprised.

How did it happen ?

Its 120v, will I be OK or should I be running to the ER ? I feel fine.

[Kiriakos-GR]

Next time put some gloves on.
Simple,  effective, and no need for ER in the future. 

[IanB]

Seems odd. What kind of light fitting is it, and did the shock stay in your hand or run up your arm?

The first oddity is that when you change a bulb, one hand is touching the glass (non-conductive) and the other hand is touching the fitting (usually plastic, but could be metal).

The second oddity is that assuming one hand was touching something made of metal, what was the live part and what was the path to ground?

I would examine the fitting closely in daylight to figure out what might be going on with it.

In the mean time, assuming you just got a zap to your hand and did not get knocked unconscious or anything like that then you will probably be fine. Especially if you went "ow!" and pulled your hand away quickly.

[Kiriakos-GR]

There is people over sensitive to electricity, and they do not even know it.

But there is no chance to find an electrician that he cannot handle a shock of CAT II 300V ... 

[diracshore]

Agreed, getting electrical gloves tomorrow, will never make that mistake again. Concerned as to why it happened. Also I have no clue how serious a shock like that is.....

So the light fitting holds 5 bulbs and I was replacing 5 60w incandescent bulbs with 2 26w fluorescents to save 248W. It actually happened twice. I thought it was just that the metal at the base of the bulb was hot the first time. The second time the shock made me let go pretty quick. Didn't really feel where the energy went. My hands had been washed and dried about 25 minutes earlier and I was wearing socks on a wood floor. So there is the path to ground, but how would light fixture pass current if it was switched off ?

I would say the shock went up my arm, thinking about it. I didn't let go myself, the electric made me let go. Just moved into this place. My UPS showed wiring fault when I plugged into the outlet earlier today. Not specific but I assumed it meant no ground since it was an old house, but according to the manual it could also mean inverted poles or overloaded neutral. Have a multimeter but not sue how to test, or even if I should be probing such a high voltage. They have fitted other newer outlets so I am using those, so i figured I was safe. It was foolish of me. Stupid stupid.

[Wartex]

Next time put some gloves on.
Simple,  effective, and no need for ER in the future. 

I thought you were an electrician, apparently not.

First of all he got shocked because the switch is miswired to kill neutral and not the hot, and the proof is that he touched the bulb thread which is supposed to be neutral. Second, using gloves to protect yourself from a live circuit may be up to Greek electric code, but in civilized countries power has to be shut off at the distribution panel with a breaker that shorts outgoing live and neutral before any work is done unless you have a certificate and appropriate training to work on live circuits, and even then additional gear may be required depending on energies carried by the circuit (and not just voltages).

What a shitty advice!

[IanB]

I have light fittings like that in my house. I'm not sure how it works in the USA but normally anything with exposed metal parts like that would need to be grounded.

If you are getting a shock then live and neutral are probably swapped in the supply wiring from the light switch. The thought just occurs--are you by any chance touching the metal base of the bulb when you are screwing it in? If so don't do that    It could be that your hand is making a connection between the base of the bulb and the metal fitting.

Two things you need. (1) is a simple receptacle tester like this. (2) is a mains voltage testing probe like one of these.

Thus equipped you can tell if each of your outlets are wired properly and you can also test for dangerous voltages where they should not be.

[Joshua]

Next time put some gloves on.
Simple,  effective, and no need for ER in the future. 

I thought you were an electrician, apparently not.

First of all he got shocked because the switch is miswired to kill neutral and not the hot, and the proof is that he touched the bulb thread which is supposed to be neutral. Second, using gloves to protect yourself from a live circuit may be up to Greek electric code, but in civilized countries power has to be shut off at the distribution panel with a breaker that shorts outgoing live and neutral before any work is done unless you have a certificate and appropriate training to work on live circuits, and even then additional gear may be required depending on energies carried by the circuit (and not just voltages).

What a shitty advice!

My dad has supplied me with rubber gloves and leather protecting outer gloves that are rated and tested to 1000V AC. These are from his days in the factory working on 480V and the like. These would definitely be substantial to protect one from the mains.

Make no mistake that there is no safer alternative than to killing power as you said, but just wanted to point out that there are gloves specifically for this purpose.

[diracshore]

In the US, at least in the places I have been, they do not provide ground to light fixtures. I doubt that I shorted the metal fitting of the fixture with the base of the bulb because the white candlestick like parts of the fixture are plastic, and I wasn't touching anything else. The shock came from my finger for sure.

IanB ,Ok, I'm going to pick up those items with the gloves and figure this out. Let me know the procedure please.

[IanB]

In the US, at least in the places I have been, they do not provide ground to light fixtures. I doubt that I shorted the metal fitting of the fixture with the base of the bulb because the white candlestick like parts of the fixture are plastic, and I wasn't touching anything else. The shock came from my finger for sure.

Standard operating procedure when screwing in a light bulb is to touch only the glass parts of the bulb with the fingertips of one hand, and to touch nothing with the other hand. If you follow that rule you cannot get a shock.

The rule is harder to follow in the UK since bayonet fittings often require the bulb holder to be steadied with the other hand. This sucks, but the bulb holder is often plastic and you can minimize the risk by treating all metal parts as if they might be live.

IanB ,Ok, I'm going to pick up those items with the gloves and figure this out. Let me know the procedure please.

The procedure is simple. The receptacle tester comes with instructions. Simply plug it into an outlet and check the indications. The mains voltage tester lights up or beeps when in contact with mains voltages. It should never light up or beep when close to any part you might touch.

[diracshore]

Yes I know, it was careless of me. i should have took a moment to think.

'First of all he got shocked because the switch is miswired to kill neutral and not the hot, and the proof is that he touched the bulb thread which is supposed to be neutral.'

How do I verify that ? touch the mains voltage tester to the base of the bulb when the light switch is off ? (wearing gloves)

[IanB]

How do I verify that ? touch the mains voltage tester to the base of the bulb when the light switch is off ? (wearing gloves)

That depends on the instructions with the tester--check what they say. The simple and cheap neon testers require you to touch a metal cap with your bare finger to make them work (it is quite safe). The more expensive electronic testers don't require this, but you still don't need to wear gloves as they have plastic cases.

[Wartex]

Next time put some gloves on.
Simple,  effective, and no need for ER in the future. 

I thought you were an electrician, apparently not.

First of all he got shocked because the switch is miswired to kill neutral and not the hot, and the proof is that he touched the bulb thread which is supposed to be neutral. Second, using gloves to protect yourself from a live circuit may be up to Greek electric code, but in civilized countries power has to be shut off at the distribution panel with a breaker that shorts outgoing live and neutral before any work is done unless you have a certificate and appropriate training to work on live circuits, and even then additional gear may be required depending on energies carried by the circuit (and not just voltages).

What a shitty advice!

My dad has supplied me with rubber gloves and leather protecting outer gloves that are rated and tested to 1000V AC. These are from his days in the factory working on 480V and the like. These would definitely be substantial to protect one from the mains.

Make no mistake that there is no safer alternative than to killing power as you said, but just wanted to point out that there are gloves specifically for this purpose.

I am aware of this, I use them at work. These protect from "touch" injuries but they fail when pierced by a sharp object like a diagonally cut conductor and they do not protect from arcing. Typically these are used to toggle energized circuits and work on live circuits with insulated tools by *qualified electricians*.  I know it sounds retarded to kill the breaker for changing a bulb, but if you live in a house with poor wiring, killing the breaker, testing the bulb socket with a voltage detector is a must before touching it. I've seen cases where entire chandelier was energized and person who grabbed it was killed and their hand burned off and separated at the wrist. They were standing barefoot on a metal patio chair on a moist concrete floor.

[Wartex]

Yes I know, it was careless of me. i should have took a moment to think.

'First of all he got shocked because the switch is miswired to kill neutral and not the hot, and the proof is that he touched the bulb thread which is supposed to be neutral.'

How do I verify that ? touch the mains voltage tester to the base of the bulb when the light switch is off ? (wearing gloves)

There is a possibility it was static buildup going out into the neutral. If you felt shaking, it was definitely AC and not static. When you bring up a non-contact voltage detector to the socket, it must not light up at all. I recommend Fluke or Greenlee ones, it's a must have for a man of the house.

[Psi]

If it was me, I'd probably connect a long wire to neutral and start touching metal objects around the house with it while looking for sparks

Yeah, it's a bit dangerous but also fun.

Note: i don't recommend you do this.

[vk6zgo]

I'd say it was neutral & active swapped over at the SPST switch,so the outer,threaded part of the lamp is "hot",

Twin contact Bayonet bases as used in Australia have both active & neutral isolated from the metal body of the lamp,so touching this part is not dangerous,even if active & neutral are transposed.(Except in the very unlikely event of  a fault in the socket .)

Unfortunately,a lot of Edison Screw crap has been let into the country,(ain't free trade grand?),so we can have the same level of danger as other countries----higher, in fact,with our 240v system!

The advice to always turn off the mains at the meter box before replacing lamps is sound.

VK6ZGO

[david77]

I obviously don't know about US Edison bases but all the Edison bases that I have ever seen here in Europe prevent the
user from touching anything live while screwing in a new bulb. Apart maybe from very old style screw bases (>50yrs.) and
damaged ones I really can't see how you'd get a shock while changing a bulb unless you deliberately stick your finger in the
base.
If I got a shock from exposed metal parts of a lamp I know what I'd do: rip the lamp down and either trace the fault or throw
the thing out.

[FreeThinker]

And people have been wondering why EE's need a special licence to work on fixed wireing https://www.eevblog.com/forum/index.php?topic=4958.0
Luckily in the US you are 120v phase to earth so you are a lot safer (but still at risk). Stop pissing about and get a PROFESSIONAL in, you are a long time dead. He will tell you you need a rewire and quote you a mind boggling price. Get it done and sleep at night. You are living (at the moment) in a death trap get it sorted before it kills you. Good luck in the mean time.

[Psi]

Stop pissing about and get a PROFESSIONAL in. Get it done and sleep at night.

Until a slug finds its way into your power sockets. https://www.eevblog.com/forum/index.php?topic=2220.0

[FreeThinker]

Stop pissing about and get a PROFESSIONAL in. Get it done and sleep at night.

Until a slug finds its way into your power sockets. https://www.eevblog.com/forum/index.php?topic=2220.0

Funny thing is I was just thinking about that post just before you commented, Spooky

[PetrosA]

Now I know how you electronics guys feel when you overhear a bunch of electricians trying to figure out something electronic

Please, don't touch mains wired shit wearing just socks. Wear shoes and use a wooden or fiberglass ladder. It's very unlikely that you'll get shocked standing on a wooden floor, but why risk it?

I'll go over the possible scenarios first:

Since this house is Victorian era in North America, there are a few ways the light could be wired and mounted. It could be knob and tube or romex (cloth covered) or BX (metal clad) with no ground. It could have been rewired in which case there is a ground. It could be mounted to a pancake box which is just screwed to the lath or the pancake could be mounted to a metal stud, or the pancake could be mounted to an existing gas lamp pipe which may or may not be grounded if still connected to the gas system. If there is one switch for this light, either the hot or the neutral could be switched, especially if parts the of the house were rewired over the years and the service upgraded. If there are two switches (3-way) and it's still the original wiring there is also the possibility that it's wired as a so-called "California" or "Chicago" 3-way, especially if the wiring is knob and tube. This type of three way switching takes a hot and neutral to each 3-way switch and feeds the light with either two hots (off), two neutrals (off) or a hot and neutral (on). This method was never allowed but was used a lot.

The lamp:

From your photo the lamp looks relatively new - less than 30 years old. The wiring in it is probably ok, but checking it with a volt meter attached to a known ground would be a good idea to see if there's voltage to the metal arms on the light. I would also check to make sure that each socket has it's paper cover under the candle cover. The paper should extend about 1/8" (4mm) above the outer casing of the socket and should cover the entire base of the bulb when screwed in. If someone used CFLs in the lamp, they may have removed the paper to get the CFL base to make contact, leaving the threaded part unguarded. It also looks like there's some kind of metal ring that goes in the top of the candlesticks for decoration. If that's the case and the paper is gone, you've got a lot of potential contact area exposed.

So there are two possible sources of shock - the metal arms of the fixture and the outer part of the socket. If checking to a known ground on the arms shows no voltage with the light on and off, check the threaded outer part of the socket to a known ground with the light on and off. If either test shows voltage with the light off, you have a switched neutral. If the metal arms show voltage in on or off, you have a short in the lamp or in the canopy.

It's also possible that the light is grounded, either because you have new wiring to it or because it's mounted to a gas pipe that's still connected to ground and that the hot and neutral are reversed, the threaded part of the socket is grounded and you touched the base of the bulb and the arm(s) of the light when screwing the bulb in. If that's the case, reversing the wires in the canopy should take care of the problem.

Whatever the case, you need to take measurements to a known ground. And wear some shoes next time

[FreeThinker]

PetrosA Your diagnostic skills are not In question but the fact remains that his system has a fault, a potentially (sic) fatal one.The fault would appear to be system wide as he states that his UPS complains of a mains fault (probably live and neutral crossed  at the service point or fuse box). There are obviously no earth leakage trips or he would not have gotten a shock (twice) and it all points to an old failing and dangerous system. Getting it sorted quickly is the only advice anyone should give, anything else is courting disaster if someone should get hurt. Shoes, Gloves and wooden stepladders are NOT the answer.

[FreeThinker]

If it was me, I'd probably connect a long wire to neutral and start touching metal objects around the house with it while looking for sparks

Yeah, it's a bit dangerous but also fun.

Note: i don't recommend you do this.

Well if your house is properly protected the first time you touch neutral to earth the earth leakage trip will operate and you will not get a spark (or only a very small one). Nice thought though

[PetrosA]

PetrosA Your diagnostic skills are not In question but the fact remains that his system has a fault, a potentially (sic) fatal one.The fault would appear to be system wide as he states that his UPS complains of a mains fault (probably live and neutral crossed  at the service point or fuse box). There are obviously no earth leakage trips or he would not have gotten a shock (twice) and it all points to an old failing and dangerous system. Getting it sorted quickly is the only advice anyone should give, anything else is courting disaster if someone should get hurt. Shoes, Gloves and wooden stepladders are NOT the answer.

In case it's not obvious, my method is to overwhelm with possibilities in the hope that they'll hire a professional

The UPS can only detect reversed wiring if there is a functioning ground as AC has no polarity. Reversing these wires at the mains box or service point could only have happened recently (since everything seemed to work fine until "Socks" decided to change out his bulbs...) if a complete idiot started poking around in the panel or meter socket. That being said, I am in complete agreement that a professional should be hired. The OP obviously isn't qualified personnel.

[Psi]

If it was me, I'd probably connect a long wire to neutral and start touching metal objects around the house with it while looking for sparks

Yeah, it's a bit dangerous but also fun.

Note: i don't recommend you do this.

Well if your house is properly protected the first time you touch neutral to earth the earth leakage trip will operate and you will not get a spark (or only a very small one). Nice thought though

Yeah, but his house has none of that or any earth connection, so a short to neutral will definitly get a responce if anything is live
If i was in his position i'd be checking every metal object in the house which uses power.
If one item is live more could be too.