fuses (or circuit breakers as i believe you meant) dont have explosives inside them. if you connected a 5 amp fuse or circuit breaker as described, it would trip and that is all that would happen. you could do it over and over and all that would happen it the fuse or breaker would trip as they are designed to do.
Grounding Electrical Question ?...help
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While it is possible for a fuse to explode if significant amounts of current are passed through it (ie, a dead short), a ground rod will NEVER provide a low enough impedance for that to happen unless you hit a water pipe with it when you drove it in.
As far as testing with a fuse, it's discussed here:
http://forums.mikeholt.com/archive/index.php/t-56380.html
As far as testing with a fuse, it's discussed here:
http://forums.mikeholt.com/archive/index.php/t-56380.html
Also here, http://www.faqs.org/faqs/electrical-wiring/part1/ and here is the exact text:
Testing a grounding electrode is a somewhat different matter.
The codes aim for a dirt-to-electrode resistance of 25 ohms or
better. One moderately safe way is:
- turn off the main panel
- turn off all of the breakers
- disconnect the grounding electrode from the rest of
the system. (often just a bolt in the panel)
- connect a 5A fuse between the output of one 15A breaker
and the grounding electrode. (use a 5A automotive fuse
in a pigtail holder)
- turn on the main breaker and the single breaker connected
to the 5A fuse.
- if the 5A fuse blows, your ground is good.
Testing a grounding electrode is a somewhat different matter.
The codes aim for a dirt-to-electrode resistance of 25 ohms or
better. One moderately safe way is:
- turn off the main panel
- turn off all of the breakers
- disconnect the grounding electrode from the rest of
the system. (often just a bolt in the panel)
- connect a 5A fuse between the output of one 15A breaker
and the grounding electrode. (use a 5A automotive fuse
in a pigtail holder)
- turn on the main breaker and the single breaker connected
to the 5A fuse.
- if the 5A fuse blows, your ground is good.
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I think the first thing is to determine where the tin ceiling is getting its current. This doesn't require anything else to be wrong except a piece of bad insulation with the hot wire touching the tin fixture.
This sounds old enough to have common ground (knob and tube) wiring ..which was adapted to breaker service. Lots of things can happen with knob and tube in terms of potential on the ground line. That is, depending on the point of access to the ground ...you can get a few sparks. Not much, since you're giving it a "competing ground path" ..but they can surely be there.
Since the tin ceiling fixture is not grounded (by design)..but obviously energized (also not by design)...the interference arc to ground is not at all remarkable. The event is odd enough ..but it's not as mysterious as a bad neutral on a newer installation ..where you may have to turn on a few lights in other rooms to allow your refrig to crank up ..or your stove giving you shocks if you happen to be at your sink at the same time.
This sounds old enough to have common ground (knob and tube) wiring ..which was adapted to breaker service. Lots of things can happen with knob and tube in terms of potential on the ground line. That is, depending on the point of access to the ground ...you can get a few sparks. Not much, since you're giving it a "competing ground path" ..but they can surely be there.
Since the tin ceiling fixture is not grounded (by design)..but obviously energized (also not by design)...the interference arc to ground is not at all remarkable. The event is odd enough ..but it's not as mysterious as a bad neutral on a newer installation ..where you may have to turn on a few lights in other rooms to allow your refrig to crank up ..or your stove giving you shocks if you happen to be at your sink at the same time.
I'm gonna take a close look at my Soares Book on Grounding- the 5A fuse thing has still got my nerves on stun...
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I had to install a copper clad grounding rod for the inspector to slap his sticker on the service panel. The water pipe thingie won't allow you to upgrade service by code. I don't recall the length ..but I had to put it at a decent angle and lay on the roto-hammer to get it in far enough into the ground.
City ordinances are what may or may not require you to use a licensed electrician. I put new services in my house and garage apartment. The electric company lady didn't know how to state the policy correctly. She kept redundantly stating "you have to get it inspected" ..I kept saying, "How can I get it inspected before it's installed?". What she needed to say was, "you need to contract an inspector to underwrite the job before you start working".
This was a conversion from old 60amp service to 200 amp service. It required the old meter(s) to be moved outside to more modern meter pans and 4 OT cable from the taps to the panel(s).
We did the work ..bridged the meter junctions ..the inspector came out ..commented that I needed another grounding rod due to my separate service disconnect and service panel ...slapped the sticker on ..signed the paper ...the electric company came out and installed new meters. Done deal ...at a fraction of the cost of paying an electrician.
City ordinances are what may or may not require you to use a licensed electrician. I put new services in my house and garage apartment. The electric company lady didn't know how to state the policy correctly. She kept redundantly stating "you have to get it inspected" ..I kept saying, "How can I get it inspected before it's installed?". What she needed to say was, "you need to contract an inspector to underwrite the job before you start working".
This was a conversion from old 60amp service to 200 amp service. It required the old meter(s) to be moved outside to more modern meter pans and 4 OT cable from the taps to the panel(s).
We did the work ..bridged the meter junctions ..the inspector came out ..commented that I needed another grounding rod due to my separate service disconnect and service panel ...slapped the sticker on ..signed the paper ...the electric company came out and installed new meters. Done deal ...at a fraction of the cost of paying an electrician.
Some communities will allow the owner to do the electrical work regardless of his/her skill level, some require a demonstration of skills and/or knowledge. In general larger communities require a licence as a demonstration of skill and knowledge. Hard to get larger than New York, but I don’t know what the rules are there.
These kinds of issues (finding a short to the tin ceiling) can be vexing, but a careful examination of any ceiling fixture(s) would be the place to start. Be very careful that you don’t make the contact worse, or become a bridge between the live electrical equipment and the grounded ceiling.
These kinds of issues (finding a short to the tin ceiling) can be vexing, but a careful examination of any ceiling fixture(s) would be the place to start. Be very careful that you don’t make the contact worse, or become a bridge between the live electrical equipment and the grounded ceiling.
Thanks guys
BITOG members are as sharp as they come !
Love reading your replies and discussion. I am learning a lot.
Update on the issue.
I have an outlet in my kitchen that I plug my fridge and microwave into. They are both on a surge protector. Well when you unplug everything from that outlet the voltage is gone. The more things operating off of that outlet raises the voltage across the ceiling to gas pipe. I turned on the microwave while the refrigerators compressor was on and the voltage jumped from fluctuating 8v to 15v.
The ceiling light at this time was shut of and breaker for it off too. The tin ceiling is not making contact with the light fixture in the center of it. The tin ceiling is about 1.5 inches from the plaster ceiling and the light box comes out of it, with no bx wiring contacting ceiling that I can see. Right now I have the refrigerator plugged in via heavy extension cord across to other side of kitchen.
The electrician will be in Tuesday to put in a rod and bonding jumper to the water pipe. They will then try to find the problem after bringing the grounding up to spec as per NEC NEC_ MIKE HOLT
Thanks again for all the replies coming
BITOG members are as sharp as they come !
Love reading your replies and discussion. I am learning a lot.
Update on the issue.
I have an outlet in my kitchen that I plug my fridge and microwave into. They are both on a surge protector. Well when you unplug everything from that outlet the voltage is gone. The more things operating off of that outlet raises the voltage across the ceiling to gas pipe. I turned on the microwave while the refrigerators compressor was on and the voltage jumped from fluctuating 8v to 15v.
The ceiling light at this time was shut of and breaker for it off too. The tin ceiling is not making contact with the light fixture in the center of it. The tin ceiling is about 1.5 inches from the plaster ceiling and the light box comes out of it, with no bx wiring contacting ceiling that I can see. Right now I have the refrigerator plugged in via heavy extension cord across to other side of kitchen.
The electrician will be in Tuesday to put in a rod and bonding jumper to the water pipe. They will then try to find the problem after bringing the grounding up to spec as per NEC NEC_ MIKE HOLT
Thanks again for all the replies coming
Be sure to tell the electrician what you have found (changes in voltage due to load on that outlet). That information will be valuable to him.
I wonder if the kitchen outlet is on a "multiwire" or Edison circuit and the neutral has a failed or failing connexion somewhere... Kinda sounds sorta like one to me with the outlet load scenario described.
Strange things can sure happen with electrical wiring, especially older stuff and/or wiring done by people who are self-taught "electricians" but in reality are perhaps better suited for wiring electric chairs...
I'm really curious as to what the electrician will find.
9c1 is right on about the value of giving that info to the electrician.
Strange things can sure happen with electrical wiring, especially older stuff and/or wiring done by people who are self-taught "electricians" but in reality are perhaps better suited for wiring electric chairs...
I'm really curious as to what the electrician will find.
9c1 is right on about the value of giving that info to the electrician.
Oh yeah I will tell him what I found and any new development.
Yeah this house has signs of "home brew electrician"
Yeah this house has signs of "home brew electrician"
^^ Everyone posted good observations and helps.^^
I just wanted to say the tin ceilings are cool.
I just wanted to say the tin ceilings are cool.
Just as a side example, Maine allows a homeowner to work on their own wiring.
They could theoretically do it for a friend as well as long as they aren't paid.
BUT, commercial and/or rental property, every switch, outlet, and strip of wire has to be done by a licensed electrician.
IDK how NY is but I doubt more lenient.
They could theoretically do it for a friend as well as long as they aren't paid.
BUT, commercial and/or rental property, every switch, outlet, and strip of wire has to be done by a licensed electrician.
IDK how NY is but I doubt more lenient.
it sounds like someone nicked a wire in the ceiling when it was nailed up. like others have said, turn off the breakers one at a time until you find the ceiling no longer has voltage present.
as i recall, nec says that you cant use pipes (gas or water) to carry a ground. of course, your water pipes should be grounded, but that should not be the source of your ground. i doubt you have grounding issues.
a megger is usually used to check for failing isulation. might be useful in this case. the poor connection from the hot side to the ceiling is going to look like failing insulation. however, most electricians dont carry a megger and you probably dont need one to find the problem.
as i recall, nec says that you cant use pipes (gas or water) to carry a ground. of course, your water pipes should be grounded, but that should not be the source of your ground. i doubt you have grounding issues.
a megger is usually used to check for failing isulation. might be useful in this case. the poor connection from the hot side to the ceiling is going to look like failing insulation. however, most electricians dont carry a megger and you probably dont need one to find the problem.
Houses built around here within the last 10-15 years have two grounds: A ground rod, and a connection to the water pipe where it enters the house.
It apparently used to be acceptable to ground to the water pipe anywhere it was convenient, but the NEC realized that widespread use of plastic pipe could render such a ground ineffective, if a section of copper pipe were replaced with plastic during a repair or remodel.
This still sounds to me like the ceiling is connected to a ground and you are seeing the effects of the phase balance.
220VAC in the US is comprised of 2 110VAC lines that are 180° out of phase, effectively it is 2 phase relative to ground, though no one calls it that. Assuming power factors of 1, if the current through both phases is equal, there will be no current to earth ground. So, if you have a high impedance ground path it won't matter, the voltage will be zero anyway. In real life this rarely if ever happens, the phase currents aren't equal (and the power factors aren't 1), so some current returns via ground. Due to this fact the voltage at the panel ground will be non-zero, given the finite conductance of the ground path. As you turn things on and off and move from outlet to outlet you are changing the phase balance, thereby modulating the current to ground and therefor the voltage on ground.
Keep in mind that ground could be either neutral or earth ground, as both are grounds, with the neutral being used to carry current.
Maybe this was mentioned. Kill all of the circuits and one by one, energize and check voltage differences between ceiling to pipe, ceiling to ground, and pipe to ground.
Thanks Sparkman.
I think I understand what your saying, but I am still learning.
Ok will check the voltages between ceiling to pipe, ceiling to ground, and pipe to ground.
The only time the voltage in the ceiling to gas pipe changes is load is applied to the outlet behind the refrigerator. I will make sure by rechecking the other outlets with some things plugged into them. Gonna use the toaster since it draws a lot of current.
I appreciate all the help coming and received already
I think I understand what your saying, but I am still learning.
Ok will check the voltages between ceiling to pipe, ceiling to ground, and pipe to ground.
The only time the voltage in the ceiling to gas pipe changes is load is applied to the outlet behind the refrigerator. I will make sure by rechecking the other outlets with some things plugged into them. Gonna use the toaster since it draws a lot of current.
I appreciate all the help coming and received already
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I suspect that the ground connection (to the common ground) for your frig outlet is compromised. This turns it into a voltage divider when current is applied. It acts as a resistive load and allows current to seek other outlets ..which it found in your ceiling fixture. I suspect if you cut an extension cord and (carefully) twist the wires (leaving them exposed) and read across them while the frig is plugged in, you'll see the difference of 120VAC and whatever is across the tin ceiling piece to the pipe. That's not the only problem ...since there's no apparent reason to have a live ceiling piece ..but it's what I reason is causing the event.
The 7 watt bulb that I had hanging connected to the ceiling and pipe got bright enough to be seen during the day. I had left only the fridge plugged in,but was able to find a heavy extension cord to plug it in across the room.
Thanks Gary,
I guess thats why no other outlet is causing the same problems.
This building has issues, my wife wants to move. This event is now added to one last year.
Last year a an outlet in the living room had a compromised insulation(whoever did bx cutting didnt use the proper tool). What sounded like a rat nibbling constantly (heard at night when quiet)was actually arcing. The arcing was slowly eating the BX line, but the breaker never tripped! In the meantime I thought it was a mouse on a mission to make a hole in that spot. Few days later I noticed it again and then decided to give the wall a whack to scare it off and what do you know, it was hot. I called the landlord and had to wait till he got home. Just before he came up sparks ended up shooting out of it and still the breaker did not trip. Only when the Landlord(RIP) opened the outlet and it arced in a huge monster blast did the breakers trip.
I would hate to have the electrician find tons of issues and then make the owner pay out the butt to fix. But looks like they took lots of shortcuts and did things very wrong.
Thanks Gary,
I guess thats why no other outlet is causing the same problems.
This building has issues, my wife wants to move. This event is now added to one last year.
Last year a an outlet in the living room had a compromised insulation(whoever did bx cutting didnt use the proper tool). What sounded like a rat nibbling constantly (heard at night when quiet)was actually arcing. The arcing was slowly eating the BX line, but the breaker never tripped! In the meantime I thought it was a mouse on a mission to make a hole in that spot. Few days later I noticed it again and then decided to give the wall a whack to scare it off and what do you know, it was hot. I called the landlord and had to wait till he got home. Just before he came up sparks ended up shooting out of it and still the breaker did not trip. Only when the Landlord(RIP) opened the outlet and it arced in a huge monster blast did the breakers trip.
I would hate to have the electrician find tons of issues and then make the owner pay out the butt to fix. But looks like they took lots of shortcuts and did things very wrong.
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