I am sure that everyone on this list knows more about electronics than i do. That said, i wanted to mention something i had to deal with concerning electrical sockets used for powering my SSE.
As you well know electrical grounding on a tube amp is ultra critical for safety and operation. I took the cover off the ac socket that i selected for my SSE and checked all wiring. Sure enough even though the socket was a 3 wire socket there was no ground!! I ran a ground wire back to the system ground (not fun). I also checked the hot and neutral to see if they were correct with the plug polarization. This one was correct.
Older homes can have all sorts of weird wiring problems. It is very easy for an electrician to cheat on an older house rewire. There is no guarantee that a ground wire on a socket is really grounded. This is not the first time i have found problems in my house.
Roy
As you well know electrical grounding on a tube amp is ultra critical for safety and operation. I took the cover off the ac socket that i selected for my SSE and checked all wiring. Sure enough even though the socket was a 3 wire socket there was no ground!! I ran a ground wire back to the system ground (not fun). I also checked the hot and neutral to see if they were correct with the plug polarization. This one was correct.
Older homes can have all sorts of weird wiring problems. It is very easy for an electrician to cheat on an older house rewire. There is no guarantee that a ground wire on a socket is really grounded. This is not the first time i have found problems in my house.
Roy
It is fairly common to find homes that were built before the 60s with recepticles that are not grounded. Many people will upgrade the recepticles, but usually don't bother to run a proper ground. All ground runs should terminate at the ground lugs in your main panel. Be extremely careful if you decide to do this yourself.
You can buy a little plug in device at most hardware stores, that you can check all your plugs with, for proper grounds as well as correct polarity.
Every home owner should have one of these in their toolbox.
You can buy a little plug in device at most hardware stores, that you can check all your plugs with, for proper grounds as well as correct polarity.
Every home owner should have one of these in their toolbox.
Attachments
If anyone is curious about the polarity (neutral vs. hot) and grounding of their household outlets, visit the local hardware store and buy a polarity checker. The one I have is made by "Ideal". Cheap and easy to use, it will display a sequence of lights, indicating correct (or not) wiring at the receptacle.
Regards,
"The Cat"
Edit: msb64 just beat my post, but the picture shows the right tool for the job.
Regards,
"The Cat"
Edit: msb64 just beat my post, but the picture shows the right tool for the job.
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It really depends on your wiring. For example, if your house is wired with conduit or BX (flexible steel armored cable), the ground path is through the conduit itself. Outlets typically connect the ground lug to the mounting bracket for this purpose. In older homes built before the 70s, you need to make sure that the ground really returns to the main electrical breaker. One of those testers can check this.
Romex (plastic sheath) has a separate ground that needs to be attached to the box or to the ground lug on the outlet for this purpose.
Romex (plastic sheath) has a separate ground that needs to be attached to the box or to the ground lug on the outlet for this purpose.
In Manitoba, the BX or conduit ground is not sufficient for ground protection.
The code requires that a dedicated ground wire be used, and it has been this way for many years. I imagine many locations have the same safety requirement.
With BX, there is also an internal ground wire, and with conduit you need to run a green covered ground wire (X-link) as well as hot and neutral conductors.
The code requires that a dedicated ground wire be used, and it has been this way for many years. I imagine many locations have the same safety requirement.
With BX, there is also an internal ground wire, and with conduit you need to run a green covered ground wire (X-link) as well as hot and neutral conductors.
My house, built in 1978 used the conduit itself for the ground. The ground and the neutral are connected together in the breaker panel. The conduit connections do corrode over time, and this practice is no longer common.
There is another major issue that I have not seen discussed here. The shared neutral. It was common in the 1970's to run ONE neutral wire for several circuits running on each phase. The theory is that the neutral current will always be lower than the current through the loads on each phase. For example if the total load on one phase is 10 amps, and the load on the other phase is 5 amps, only 5 amps flows through the neutral. This works fine, until the neutral goes open. Then the phase with the smallest load will see more than 120 volts. The neutral wiring is daisy chained through each wall outlet.
Combine that with the (still common) electrical outlets that you simply strip the wire and stick it into a hole in the back of the outlet. The spring steel contacts will loose tension over time, and ZAP! One outlet fried after 10 years, but it might have been a bit overloaded with Christmas lights. It was the hot wire that fried, so only the outlet was damaged.
The second incident came when Sherri plugged in the vacuum cleaner (serious start up current) and stepped on the switch. She said that lights flashed, the clock radio in another room caught fire and the offending outlet started smoking. It also casued the MOV's in two surge supressor strips to blow up (saving the TV). One looks like it was near flames before the breaker popped.
That incident resulted in the replacement of every wall outlet in the entire house.
There is another major issue that I have not seen discussed here. The shared neutral. It was common in the 1970's to run ONE neutral wire for several circuits running on each phase. The theory is that the neutral current will always be lower than the current through the loads on each phase. For example if the total load on one phase is 10 amps, and the load on the other phase is 5 amps, only 5 amps flows through the neutral. This works fine, until the neutral goes open. Then the phase with the smallest load will see more than 120 volts. The neutral wiring is daisy chained through each wall outlet.
Combine that with the (still common) electrical outlets that you simply strip the wire and stick it into a hole in the back of the outlet. The spring steel contacts will loose tension over time, and ZAP! One outlet fried after 10 years, but it might have been a bit overloaded with Christmas lights. It was the hot wire that fried, so only the outlet was damaged.
The second incident came when Sherri plugged in the vacuum cleaner (serious start up current) and stepped on the switch. She said that lights flashed, the clock radio in another room caught fire and the offending outlet started smoking. It also casued the MOV's in two surge supressor strips to blow up (saving the TV). One looks like it was near flames before the breaker popped.
That incident resulted in the replacement of every wall outlet in the entire house.
Yee-haww! My house was built in the early part of the 20th century, and has a bastard chimera mix of romex and ancient post-and-tube wiring. I plant to strip it out and rewire it a circuit at a time, if for no other reason than to know absolutely where things are going (and adding grounded receptacles, of course). Ancient electricians had a habit of just tapping into existing wiring, with the result being a maddening crazy-quilt. Fortunately, I have a full basement, so rewiring need not be all that harrowing an experience.
I have seen some rather scary stuff, so comparitively this place isn't too bad.
Sherri's mothers house, built in 1921 sounds like yours. The original wiring is still live, and most of the cloth insulation is intact. The sacry stuff is all of the "additions" made by previous and the current owner. The electric meter spins with all of the fuses removed from the box! After I cut the wires to the detached garage the phone started working and things in the basement don't shock you any more.
Sherri's mothers house, built in 1921 sounds like yours. The original wiring is still live, and most of the cloth insulation is intact. The sacry stuff is all of the "additions" made by previous and the current owner. The electric meter spins with all of the fuses removed from the box! After I cut the wires to the detached garage the phone started working and things in the basement don't shock you any more.
I don't think mine's quite that bad, but I really couldn't tell you where everything goes - not a good thing. My place is old enough to have a rusty old rivet-studded water tank of some sort in the attic, and it was probably heated originally with coal. My neighbor's place has similar little bits of antiquity, like a hutch over the stove for a kerosene tank.
Our house was built in 1910 and had mostly knob and tube wiring on the second floor until a few years ago (Christmas 2006) when I apprenticed with a local electrician and we rewired that floor. You might not believe some of the things we found.. 
There was some relatively amateurish wiring done by a previous owner down in the basement which I ripped out and replaced. Most of the first floor was rewired in the 1940s and 1960s so we have a mix of BX and Romex with a 20ga ground wire, better than nothing, but not much.. Most of the grounds had gone open because rather than being secured to screws inside the junction boxes the ground conductor was wrapped multiple times around the jacket and clamped. Over the years the clamps loosened up. I removed every one of those connections and secured them with screws inside the junction box - where possible I pulled modern Romex to replace the old cables. The kitchen has a lot of new heavy duty circuits for appliances that no one was dreaming of even in the 1960s..
The original service was replaced in 2004 and in six years we have filled every single breaker location although fortunately we are not near the ampacity limit of the service or panel.
I have replaced most of the older outlets in the house, and made sure to use the screw terminals.
It pays to check the condition of exposed wiring and outlets from time to time..
Ah, the idiosyncrasies of old houses (and often former owners.. )
There was some relatively amateurish wiring done by a previous owner down in the basement which I ripped out and replaced. Most of the first floor was rewired in the 1940s and 1960s so we have a mix of BX and Romex with a 20ga ground wire, better than nothing, but not much.. Most of the grounds had gone open because rather than being secured to screws inside the junction boxes the ground conductor was wrapped multiple times around the jacket and clamped. Over the years the clamps loosened up. I removed every one of those connections and secured them with screws inside the junction box - where possible I pulled modern Romex to replace the old cables. The kitchen has a lot of new heavy duty circuits for appliances that no one was dreaming of even in the 1960s..
The original service was replaced in 2004 and in six years we have filled every single breaker location although fortunately we are not near the ampacity limit of the service or panel.
I have replaced most of the older outlets in the house, and made sure to use the screw terminals.
It pays to check the condition of exposed wiring and outlets from time to time..
Ah, the idiosyncrasies of old houses (and often former owners.. )
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My sisters house, built at the end of the 19th century, is a blend of everything. Mostly knob and tube with much of the insulation gone in the exposed areas. Walking in the basement, with its low ceiling, requires that you know where your hands are at all times! It's a rats nest of bx with multiple fuse boxes. When something goes wrong, it quite an adventure to unravel th problem, lol.
If it's "ultra critical" to have a 3rd wire ground, how did all those millions of tube radios, televisions and stereo units operate in the 40s, 50s, 60s, 70s,....?
Why aren't we all dead?
G²
Well...it almost happened to me (dead that is).
When I was around 12-13, I started to "play" around with radios. I stripped an old 5 tube radio out of it's case, and plugged it in to watch the tubes light up. Not aware that the metal chassis was at 110v above ground, I picked it up with both hands. I was standing on the concrete basement floor in bare feet. Lucky to live through my first lesson in electricity!
Those outlet testers can be fooled. In a correct installation, the ground wires for the outlets meet at a ground bar in the main breaker panel along with a heavy-gauge wire running to a grounding rod -- sometimes multiple rods. The neutral also connects to this ground bar. The testers are fooled if you wire the neutral to the ground screw on the outlet itself. The tester will claim the outlet is wired correctly, even though there's no ground protection.
~Tom
~Tom
Good point, an unusual situation, but entirely possible when "home handymen" are involved.
I have come across where a person ran a recepticle off of a switch leg. The switch leg did not have a neutral, just a hot line wire, hot load wire and a ground wire. They connected the hot for the recepticle to the hot side of the switch, and connected the neutral of the recepticle to the switch ground. As stated by Tom, neutral and ground should only be connected in the main panel. Using a ground wire as neutral is way beyond dumb and can easily be fatal.
Another thing to keep in mind is that you can have some serious current flowing through the heavy neutral wire that runs to ground rods and possibly even to your water main. Do not even think about touching that wire with your main panel energized.
But you weren't "qualified personnel" - nor was I back then. If you HADN'T been taking it apart, would you have gotten a shock? I think not BUT if you dropped it in a bathtub while you were in it, you WOULD have been killed. Now we have GFCI protectos and while they're _supposed_ to handle these kinds of faults, _I'M_ not about to do that experiment.
G²
"qualified personnel"
Ha!
Yeah...if the old Philco would have had a sticker warning: "No Owner Serviceable Parts", that would have stopped me for sure.
Ha!
Yeah...if the old Philco would have had a sticker warning: "No Owner Serviceable Parts", that would have stopped me for sure.
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