Please help. I just installed two 2 pole light switches in the bedroom
(they should have been 3 pole). When I went to turn on the power it
tripped a breaker so I knew it was not right. I looked online and
found I should have bought two 3 pole switches, so I went to HD and got
2 of them. Now they are both installed, but I am unable to turn on the
light. When I tested with a multimeter I found only one switch has
power going to it while the other has none. Anyone have a clue what
happened? Did I 'fry' the wires? What do I do now?
There are single pole and three way switches. For you to have tripped the
breaker you must have installed one of the "extra" wires onto the ground
terminal. The three way switch that has no power is that way either because
of a tripped breaker or because its corresponding three way switch is in the
position that doesn't send power to it. You need to get a drawing of how
three way switches are wired or hire someone to help you
Assuming there were 3-way switches and the proper number of wires there
already, installing new 3-way switches correctly should get it working
The breaker will have protected the wiring, so it is very unlikely you
Go back to Home Depot and buy a book on basic electrical wiring.
You don't know what you are doing now, but your post is intelligible
enough so that I'd guess with a book to guide you you'll come up to
Would you be willing to try clenching your right hand around a bare hot
feed wire and your left hand around its bare neutral wire and depend on
the upstream 15 amp breaker to "protect" you?
I suspect not.
The breaker "protects" the wiring and devices to the best of its
ability, and the relatively new arc fault detecting breakers add another
dimension of protection.
Breakers are there to limit heating caused by overcurrents and by so
doing prevent fires. Thus, they only indirectly "protect" humans.
I stand by what I wrote, the OPs "wiring" wouldn't have much chance of
being damaged because the breaker (which popped) would have protected them.
You are, of course, technically correct. I didn't mean to say your entire
point was wromg. It is not. And I should have said "protect the humans from
In a "hard short", when the hot lead is inadvertantly connected to the
nuetral lead on a connected device, the breaker does not cut the current
fast enough to protect *every* device. This applies far more to electronic
devices connected to the circuits ( see http://www.bcae1.com/cirbrakr.htm )
than dumb devices like wall switches, and this is the point I was trying to
alert people to. But even a wall switch can be damaged in a hard short
("though rare") particularly if it had a slight defect to begin with. With
all of the microelectronic circuitry built into so many devices used in
homes today, in addition to the big ones like computers, TVs, and sound
equipment, it would be less than accurate for people to believe that the
circuit breaker will protect those devices from damage. It will not.
And, "while rare", the OP *could* have damaged the switch if he hard shorted
Agreed, and for my part I should have been even more specific by
defining "wiring" as being just the conductors and nothing else. I was
trying to reassure the OP that there was little chance that he would be
facing tearing down wall and ceiling plasterboard to replace his Romex
or whatever was in place.
And yes, I agree that the extent of the damage to electronic equipment
stemming by internal faults in the equipment itself can be less if a
fast acting overload device interrupts the power feeding that equipment.
But the realities are that in most cases whatever fault occurred in that
equipment to cause the overcurrent condition isn't going to go away by
itself and probably the cost of a professional repair will make the
owner junk the equipment in favor of replacing it anyway. <G>
Jeff Wisnia ( email@example.com) said...
Many people think electric circuits work using the "theoretical model"
taught in school science class (i.e.: perfect conductors with zero
resistance, voltage sources with no internal impedance, etc).
To that, this thinking extends to the idea that a circuit breaker trips
at the instant the current exceeds its rating.
In actual fact, a circuit breaker is a thermal device that takes time
to react to current in excess of its rating. As short as that time is to
us humans, durinig that time there is the entire generating capacity of
the grid you get your power from behind that current (less the impedance
of the transmission network). Suffice it to say, in that short instant
the current can reach a VERY high level. Many panels and switchgear will
have a peak current rating of 10,000 amps or higher for this reason.
I agree - the "wiring" wouldn't have much chance of being damaged.
However, some switch contact where the short occurred probably now has a
nice little dimple on it where the short lived short circuit current spike
vapourized it. Not likely to effect its future operation, unless you
continue to repeat the same action a number of times.
"I really think Canada should get over to Iraq as quickly as possible"
I agree with all that Jeff says.
FTR, they are called 2-way and 3-way, terms of art, used only in 110
volt electricity**, afaik.. None except 4-way is more than one pole.
**And maybe in Europe they use the same terms with 220 volt
electricity. I don't know about Africa and Asia!
2-way is single-pole, single throw, and
3-way is single-pole, double-throw.
4-way is double-pole, double-throw, and it is assemble so the two
throws reverse the poles. But you're not quite ready for 4-way yet.
Remove NOPSAM to email me. Please let
me know if you have posted also.
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