On Nov 28, 2:15*am, Tony Hwang wrote:
wrote:
On Nov 27, 2:15 am, "Kevin" wrote:
I just finished wiring in two 220V circuits to the shop -- 1 for the dust
collector (5.5A), and the other for the tablesaw (14.5A), jointer (6.5A),
and tbd.
Just for grins I put all of them onto the one circuit. *So 5.5+14.5+6.5 =
26.5A. *The 20A breaker did not trip. *I even tried starting up the tablesaw
while the others were running.
Now in practice, I will keep my dust collector (5.5A, 1.5HP) on it's own
circuit, but apparently I could concurrently run both the tablesaw (14..5A)
and the jointer (6.5A) and possibly even a 3rd TBD on that other circuit.
How is that? *The real load must be under 20A, or the 20A breaker allows
more like 28A.
I first tried the TS and Jointer, and when they did not trip the breaker
(total 21A), I added the DC. *I was surprised all three did not trip the
breaker. *But I guess each was running with no load, so that is surely
another reason.
Curious,
Those ratings are for machines with a maximum work load. * In other
words, a saw just spinning doesn't pull as many amps as one ripping a
big piece of wood. *If you put them to work instead of just spinning
them up, your results would be different.
Hi,
And motor starting surge current is for split second more than that.
Quite unlikelt all 3 devices will be active simutaneously. Also circuit
breaker has several different typr. One will trip instantly when
overloaded. One will have a delay to trip and one which is temperature
compensated, etc.- Hide quoted text -
- Show quoted text -
Exactly. Sounds like an extreme case of of multihanded/multi tasking!
If all the appliances and services in our homes were switched on at
the same instant and then continued to impose that requirement
continuously, the load on the electrical supply system would be
tremendous!!!!!!
For example there is 200 amp service into our house.
Our maximum load would be 200 x 230 = 46,000 watts. (46 kilowatts). If
continuous over 24 hours that would be 46 x 24 = 104 k.watt.hrs. of
consumption. In actual fact our average daily consumption (including
electric heating) at the moment (late November) is around 40 to 50
k.watt.hrs per day; an average of less than 2 k.watt.hrs per hour!
Sometimes even if/when our bench saw (Plugged into a 230 volt circut
work shop outlet) jams on a piece of old wood it doesn't even then
trip or blow the ancillary 20 amp fuses located between the breakered
feed and the workshop outlets.
By the same token some people do overload one circuit and then wonder
why they can't plug the coffee maker, an electric fry-pan, a toaster
and the microwave oven all into one kitchen outlet circuit; and THEN
switch them all on at the same time to make breakfast
When the breaker tends to trip (and wear out prematurely) they then
blame it on 'an electrical problem' rather than 'user error'!
The same people would not try to put an 11 person soccer team plus all
their gear into one small car. Have eight people take showers all at
once in a single home bathroom. Put four cars in a two bay garage etc.
etc.!
So it's hard to understand the lack of logical thinking that wires and
circuits and most of the things we use are normally much more lightly
loaded than the conditions designed to trip breakers (or blow fuses of
the correct size) and protect against fire etc.
Seen a couple of recent installations with 20 amp outlets (as opposed
to 15 amp) near kitchen counters. Individual outlets designated by
NMEA outlets with a 'T' configuration of one of the pin sockets. Seems
like a good idea?