I’m going to stay out of this debate on
power sources for the
dimmer pack. The good, the bad and mostly the confusing to figure out so as not to muddy the waters further.
In plugging into outlets however, what the
receptacle is and how many other receptacles are on the same
circuit as it often become a problem in thinking. Short of a
circuit breaker finder and a plotted out room, much less an amp probe to test normal amperages on circuits in case they were tied into the
house lighting, it’s very hard to determine how much load is available on any single
outlet amongst many.
Often there will be a 15 amp duplex
outlet in a
house on a 15 amp
circuit breaker. More often than having a single
outlet tied to a
breaker however there will be many more outlets if not even overheard lighting in this room or outlets and lighting in other rooms tied together all on this 15 amp
circuit breaker. At other times such as in a kitchen, the outlets might be the same but due to the higher expected
current needs, such outlets tapped off a
breaker or as a series of them will be tapped off a 20 amp
circuit breaker. As a rule a single
outlet tied to a 20 amp
breaker will be of the 20 amp type, but frequently often also there will be a few outlets tied to this same 20 amp
circuit just as on a 15 amp
outlet there can be more than one output as per
NEC rules.
In this way, the only major rule (beyond rules for calculating load or how many outlets per
breaker) of
outlet type or number of them on a
circuit would be that a 20 amp
receptacle cannot be
fed by a 15 amp
circuit breaker.
All of this does not on the other
hand ensure that if you have a few outlets on the same wall they are not on the same
circuit breaker just because they are in different locations. It also does not assure that on a duplex
outlet, just because there is an open place to
plug in, that the second
outlet will allow more
power to be tapped off the
receptacle. It is possible and easy to often split the
outlet’s bridges and
power it up from two sources so a duplex
outlet is more like two single ones, but this is often also fairly rare to see commercially done without specific intent that is often noted on the
outlet. In which case more frequently it would be 20 amp in feed - why bother otherwise.
In other words, just because you have an open
outlet on a
socket, or there are other outlets on a wall, this does not always mean you have more
power available to you. Often in more modern wiring such rooms will have two or more outlets that are not a common
breaker, but in older times where
current draw was overall just a question of convent outlets, they were often powered from the same source as an improvement to one or two outlets per room at best. Older wiring even if on a 20 amp
circuit breaker should also be suspect. Frequently someone will install a 20 amp
breaker even if the wiring feeding it is only rated for 15 amp on older installations thus the fire hazzard should you overload something short of careful study.
Be very careful about plugging stuff in and where.
At one
point I was paid to design a new theater and office space. Here I spent hours upon hours maximumizing the
layout much less distributing and balancing the
power requirements for the building. Say two office complexes, one theater, and one rehearsal
hall per floor. The plans were approved of by the architect and general contractor than handed off to the Polish electricians who barely spoke English and tended to test for
power with a touch of the
wire, as opposed to a short to shut off the
circuit breaker. They had this constant problem of tying all outlets on an entire floor into about three
circuit breakers, and all lighting into one or two more when not wiring hot for 120v and
neutral for a opposing
phase of 120v. These being a bad example of electricians, simple and quick is still the goal within
safety limits. Don’t expect that unless you specified and tested a
circuit to be
fed individually and specifically for a purpose that there are not other taps on it in other locations in the room or elsewhere in the complex.
Available outlets are one thing, available circuits without other taps on them are often another.