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any 120v electricians here?


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oldspark 
Gold - Posts: 4,913
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Joined: November 03, 2008
Location: Australia
Posted: November 10, 2010 at 9:47 PM / IP Logged  
You are wrong on both counts.
Why would you have a ground to a switch? (Whether your ground is an Earth or Neutral does not matter.)
If those people telling you it "Must" have, then I'll assume that they are qualified people and therefore know that Regulations require that that be done.
But that is then becuase of Regulations - NOT because the switch needs a ground to function.
A shorting switch?
Do you mean that it is worn out so that is shorts the input to the output?
In other words, the switch is permanently on?
How does having a switch turned on trip the breaker?
A switch is a short circuit between 2 terminals. That is their intended design etc.
I'm not saying that a faulty switch cannot trip fuses & breakers, but it WILL NOT be because of an internal short.
And from what you said above, it is not possible for your switch to trip the breaker.
Hence I want to find out why your breaker is tripping.
It may be the switch, but it may be a problem elsewhere.
And you need to find out.
So have another go...
How does a faulty switch trip a circuit breaker?
An why does your non-existent ground wire(s) to the switch have to be there?
These are VERY SIMPLE domestic electrical questions.
Anyone that cannot answer them should be very wary of what tragedy may occur in the future.
And if you can answer them, you might understand why a 1.2V reading is 1.2V, and it might eve read zero volts even though are measuring a 120VAC or 240VAC wire.
kenwood_nut 
Stock Boy - Posts: 227
Stock Boy spacespace
Joined: April 10, 2009
Location: Washington, United States
Posted: November 10, 2010 at 9:57 PM / IP Logged  
Thanks once again! I copied everything you've sent me to a Word document for reference in the morning.
But a few notes in regards to what you mentioned that I said...
I was told by a couple people that there shouldn't be a ground to the switch. But now they way you explain it, that all makes sense. So what you mean is I should ground the BODY of the switch and NOT the actual switch terminals? This is what I was thinking.
And about the breakers tripping: When I flip the old switch, it trips the breaker. Not sure why. But I'm "guessing" there is something bad inside it. If I flip the breaker, it won't re-trip. Not until I move that switch. I'm just guessing it has a short inside it. That's all I was trying to say.
Again, I do appreciate all the advice everyone has given me!!! I will use as much as I can to solve my problem. And like I said, ALL that I'm trying to do is keep power to my garage door opener. I don't care if there is a switch or plug there or nothing.
flobee4 
Silver - Posts: 585
Silver spacespace
Joined: January 02, 2004
Location: United States
Posted: November 10, 2010 at 9:57 PM / IP Logged  
I'm sorry if I didn't explain the ground part. There usually is ground running to the actually box and even through the box to the actual light or electrical outlet that is being switched. But, is NOT used in the actual switching. I didn't bother to explain that because to make the switch work, it doesn't "need" a ground. As far as code goes, I'm sure there is supposed to be either a ground wire in the box to connect to the switches separate ground screw or the box itself is grounded and then the box is grounded to the ground screw of the switch, as per code.
A 3-way switch needs 3 wires to work and that's what you have. So, that means there is no ground wire in the box. it is possible that they grounded the box. But, I doubt that because you should have gotten 120 volt reading off one of those 3 wires when you placed the black test probe against the box and red probe against the 3 wires.
The neutral and the ground are connected to the same spot in the electric panel. While its ok to use either for testing for a hot lead with a meter, a ground and a nuetral cannot be interchanged. Thats why you are using the extension cord, to supply you with a testing point.
kenwood_nut 
Stock Boy - Posts: 227
Stock Boy spacespace
Joined: April 10, 2009
Location: Washington, United States
Posted: November 10, 2010 at 9:59 PM / IP Logged  
I can't believe how different 12 volt vehicle wiring (which I'm very familiar with) is from house wiring!!! Holy cow, I never imagined home wiring would ever by so tricky until I came across a 30-way switch!
i am an idiot 
Platinum - Posts: 13,666
Platinum spaceThis member consistently provides reliable informationspace
Joined: September 21, 2006
Location: Louisiana, United States
Posted: November 10, 2010 at 10:25 PM / IP Logged  
any 120v electricians here? - Page 2 -- posted image.
kenwood_nut 
Stock Boy - Posts: 227
Stock Boy spacespace
Joined: April 10, 2009
Location: Washington, United States
Posted: November 10, 2010 at 10:38 PM / IP Logged  
Thanks, man. But the Single Pole is much more different than the 3-way. Mine basically "looks" the same though. It does have the ground tab.
Now I'm wondering if before I wrap things up, SHOULD I run a ground wire from the new switch's ground tab to the actual box? or not?
Thanks everyone! I really needed this help! Like I said, it's amazing how complicated home wiring is (with only 3 wires) as apposed to vehicle 12-volt systems (with a million different wires)!!!
KPierson 
Platinum - Posts: 3,527
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Joined: April 14, 2005
Location: Ohio, United States
Posted: November 10, 2010 at 10:45 PM / IP Logged  
If the box is metal AND the box is grounded then you should connect a ground from the switch to the box. If the box isn't grounded then there is no point to connect the switch to the box. In a typical house that was not wired with grounds the metal boxes are left floating.
If you understand Bosch relays then you should understand 3 way switches. The actual switch acts as the coil of the relay, and the three terminals on the side of the switch represent 30, 87a, and 87. Back in college I used a DEI channel expander driving a 12vdc SPDT switch connected to a 3 way switch to be able to toggle the lights in my apartment from my car alarm remote.
Kevin Pierson
oldspark 
Gold - Posts: 4,913
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Joined: November 03, 2008
Location: Australia
Posted: November 10, 2010 at 11:21 PM / IP Logged  
kenwood_nut wrote:
I can't believe how different 12 volt vehicle wiring ... is from house wiring....
I stated this reply after that message. A few delays and a few other replies have crept in.
But FWIW.... (yes, a ramble...)
Well the switching is the same - you only need to switch the one pole.
Hence why you do not need other pole (ground).
But domestic AC usually mandates the switching of the ACTIVE conductor except where BOTH poles are switched (eg double-insulated).
Whereas that - and its logic - may not apply in car etc. A classic example that has recently resurfaced yet again - a "Battery Isolation Switch" that is used in competition etc vehicles to enable isolation of the battery in case of accident etc SHOULD be in the non-HOT circuit - ie, it should disconnect the battery's negative (ground) terminal from the chassis and loads etc. If the switch is next to the battery, it is no big deal. But when regulations require an isolation switch to be on the dash or console, or a rear corner of the vehicle, then isolating the +12V side is suicide! Some argue that in that case, it is safer with NO switch!
Now, do you ground the box etc?
My answer to that is "why create an additional risk?".
But your local regulations will state what is required. Refer to them.
(If your local regulations are a hazard, I empathise.... Been there, Done that!)
It sounds like you have the ever popular M.E.N system. (IE - power station outputs 2 AC lines - aka L1 & L2. They call L1 "Active" and bond L2 to (planet) Earth and call that "Neutral".
The Active L1 is distributed across the country.
Your Active goes via a fuse to your switchboard main switch and thence through fuses to different circuits (lights, power, kitchen, etc).
The Neutral also comes in to the main switch board (aka MSB) where is is bonded (joined) to an Earth Stake, otherwise Earths and Neutrals are kept completely separate in home wiring.
Earths are often literally just that - an Earthed connection meaning to planet Earth. Or yes, also called ground.
The Neutral however is the "return" for the Active circuit.
Power flows out the power station through the active, through the load, and back through the Neutral back to the power station.
That method means that fuses will operate given certain kinds of faults, and appliances should be at Earth potential so you don't get zapped. (Until lighting hits telephone lines etc... LOL!)
And the above is a simplification. In reality, 3 phases are sent from the power station, not "active and neutral". They are like three L1 lines or "actives" that are 120 degrees apart (aka 3-phase power). And there is no Neutral per se - "neutral" is a mid point between the 3 actives. (Neutral may be "reconstructed" at substations for distribution to consumers.)   
But whereas the AC system used to be almost a floating or balanced system - ie, 2 pins and no Earth - the world is standardising on an Earthed distribution system - ie, 3 pins - Active (brown), Neutral (blue) and Earth (green or GREEN/ YELLOW).   
Remember - if you touch the Brown, you will s.h.i.t yourself (poo your pants if that gets censored). That's how I remember. We used to have red = active and black = neutral and green = earth. They were easy to remember (red is hot and dangerous).
So back to your question. Do you ground the box?
Well, do you mean ground as in neutral, or ground as in earth?
Our regulations are quite clear - any mains (wall) powered device shall be in an earthed (metal) enclosure EXCEPT where it is a double insulated appliance (only 2 wires; special construction applies).
And earth means earth - the 3rd pin with its GREEN/ YELLOW wire to an "earthed ground stake" - NOT to the neutral pin or circuit.
So, refer to your regulations.
But I am certain that if you did that, you would be replacing your green wires. In most places in the world, that is a serious hazard - an accident waiting to happen.
As to your breaker tripping, as you should be able to appreciate, there is no way that the switch can short so as to cause MORE current to flow through the circuit (light) than the switch itself (ie, a clean contact switch).
So, is it an arc across the contacts that generates noise that trips the breaker?
Or is the breaker an RCD (aka earth or ground switch, aka "Safety(sic) Switch") that likewise is getting noise and tripping?
Or is the switch "leaking" through you or something and tripping the RCD?
Or is there an insulation breakdown so that when moved, there is leakage through <whatever> which is tripping the RCD?
The latter is often followed by fire.
The latter two are often followed by death, else maybe a cute shock if an RCD is installed AND is working properly (people rarely test them; hence they seize!).
I did write "a cute" shock because of my sick humor, but make that one word if RCDs are not fitted or if you place yourself across the neutral and active (without any earth leakage) as such shocks often are acute.
Forgive my narky attitude, but I no longer suffer Richard Craniums (aka Dik Heds).
And I do laugh - because seeing preventable tragedies is something I also try not to suffer. (Though it was funny seeing that guy on a train light up; fall stiff as aboard to the roof (making a hollow wooden sound as he did); then having spot-fires gradually ignite over his body. 1,500V DC - I'd rather 22,000V AC any day!)   
But you may now understand some of my questions....
And you did give the answers I expected.
For some reason, people think switches must be earthed or neutralised. (Yet they know their ignition switch isn't, nor their 2-terminal switches.)
And for some reason, people think that short circuits blow things. [ EG - A common one - you keep blowing light bulbs; people often say "you must have a short". So how do you short a 12V supply into a 12V bulb? Else how does a short ACROSS a bulb blow it (assuming short intermittent shorts so that the fuse doesn't blow)? It's more likely a bad connection that makes & breaks - hence thermal shock etc. ]
Alas it doesn't take much thinking to realise the reality, it's just the we rarely do think...
Yet in retrospect it is all so obvious and easy....
kenwood_nut 
Stock Boy - Posts: 227
Stock Boy spacespace
Joined: April 10, 2009
Location: Washington, United States
Posted: November 10, 2010 at 11:21 PM / IP Logged  
Wow, what a concept! Yes, I do understand Bosch relays (in fact I have about 50 pages of info on them, all from the12volt!!!
My box IS metal. No ground. But my best friend said back in the 30's to 50's and stuff, they didn't use grounds in switches. Sure, things have changed, but that's part of why I'm having problems. Apparently wire colors changed too!
But I think I have it all figured out. A couple people have sent me very helpful tips and info that I have no doubt will help.
THANKS SO MUCH to everyone who replied. I really needed it, and was losing hope!
i am an idiot 
Platinum - Posts: 13,666
Platinum spaceThis member consistently provides reliable informationspace
Joined: September 21, 2006
Location: Louisiana, United States
Posted: November 10, 2010 at 11:22 PM / IP Logged  

Turn off the breaker that powers this circuit.  Remove the switches one at a time, using an ohm meter, check to see which of the 2 terminals show a dead short on the meter.  Now connect the 2 wires that came from those 2 terminals to each other.  That switch is not out of the circuit.  Insulate the remaining wire and turn the breaker back on and check to make sure all works.  if so, kill the breaker again and do the same with the other switch. 

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