How many items on a breaker

[olly]

Thank you for a simple reply in this case. I am a Master Electrician, of course I know 20a 12AWG and 15A 14AWG, and how many Watt would total 80%. How the heck can you calculate what someone may plug in? Thats why you must have a magic #. Thank You

 

[James L]

Each receptacle counts as 180va which is 1.5 amps.

and it's not counted as continuous load.

10 receptacles on a 15 amp circuit
13 receptacles on a 20 amp circuit

 

[iwire]

Each receptacle counts as 180va which is 1.5 amps.

Not by code for a dwelling unit. There is no NEC value for a dwelling unit receptacle.

and it's not counted as continuous load.

That is a fine choice but again not set by the code.

 

[JFletcher]

Sometimes you need to exceed the NEC; to wit:

We are wiring a rather large new home (5000sqft). The downstairs bathroom has 3 4 lamp vanities, which can accept (by the vanity mfg) 100W bulbs. If the HO lamps it this way, the vanity lights alone will draw ~10A, leaving little for anything else on that circuit, let alone something common like a 1800W hair dryer. Doesnt matter if it's continuous or not, even 12 60W bulbs (and fart fans and recessed lighting) + hairdryer on a 20A circuit may leave someone in the dark.

 

[kwired]

Sometimes you need to exceed the NEC; to wit:

We are wiring a rather large new home (5000sqft). The downstairs bathroom has 3 4 lamp vanities, which can accept (by the vanity mfg) 100W bulbs. If the HO lamps it this way, the vanity lights alone will draw ~10A, leaving little for anything else on that circuit, let alone something common like a 1800W hair dryer. Doesnt matter if it's continuous or not, even 12 60W bulbs (and fart fans and recessed lighting) + hairdryer on a 20A circuit may leave someone in the dark.

So we have possibly 400 watts of lamps plus 1800 watts of hairdryer=2200 watts.

How often do you see a hair dryer run for 3 hours or more to have to consider it at 125%? Even Sasquatch can probably dry himself within 3 hours.

 

[templdl]

Sometimes you need to exceed the NEC; to wit:

We are wiring a rather large new home (5000sqft). The downstairs bathroom has 3 4 lamp vanities, which can accept (by the vanity mfg) 100W bulbs. If the HO lamps it this way, the vanity lights alone will draw ~10A, leaving little for anything else on that circuit, let alone something common like a 1800W hair dryer. Doesnt matter if it's continuous or not, even 12 60W bulbs (and fart fans and recessed lighting) + hairdryer on a 20A circuit may leave someone in the dark.

Lighting loads ofted a fairly constant ase it is dependent upon the wattage served. I would target tty hat first based upon using #14 wire proted with a 15at breaker and a max load of 1440ww. I would also consider (2) lighting circuits in an area which would provide some security should for some reason one circuit trips you still have lighting in that area. Fart fans certainly are not a significant load.
The consider the plug in loads such as hair driers. Basically any heating load can be significant which can be addressed with addition #12 wire with 20at breakers.
Another thought is the number of outlets an how to reduce the need for power strips and other multiplug addaptors such as using quads outlets instead of the common duplex outlets.
Also give some though to decreasing the distance between outlets.
Again, extra circuits see preasd out the load reducing the chances of tripping a breaker.
It is during rough in that you can you can try to prevent the regrets of the I wish I could have would haves.

 

[JFletcher]

So we have possibly 400 watts of lamps plus 1800 watts of hairdryer=2200 watts.

How often do you see a hair dryer run for 3 hours or more to have to consider it at 125%? Even Sasquatch can probably dry himself within 3 hours.

12x60W= 780W, which is 6.5A. A 1800W hair dryer (some are 1950-2000W) is 15A. That's 21.5A on a circuit, *IF* the HO doesnt lamp the vanities with 75 or100W bulbs. If s/he does the latter, that's 10A (12 100W bulbs) + fart fans (minimal load) + recessed lights (again, minimal load) + hairdryer (1800+W; 15A). That's 25A+ on a 15 or 20A breaker (assuming nothing on the upstairs bathrooms). I would hope the breaker would trip in <3 hours with that load. Hair dryers can run for 20min or more...

Now, if they use 40W incandescent (or 25W) or fluorescent or LED, there wont likely be a problem. But on a three-quarter million dollar home, I would prefer there be no chance of problems.

 

[480sparky]

Sometimes you need to exceed the NEC; to wit:

We are wiring a rather large new home (5000sqft). The downstairs bathroom has 3 4 lamp vanities, which can accept (by the vanity mfg) 100W bulbs. If the HO lamps it this way, the vanity lights alone will draw ~10A, leaving little for anything else on that circuit, let alone something common like a 1800W hair dryer. Doesnt matter if it's continuous or not, even 12 60W bulbs (and fart fans and recessed lighting) + hairdryer on a 20A circuit may leave someone in the dark.

You wire all the lights on the 20a bath circuit?

 

[kwired]

You wire all the lights on the 20a bath circuit?

I often do and never have any callback issues.

20 amp breaker should hold at 20 amp load indefinitely, give it some age and a chance for things to degrade and that may change. Still should hold for long enough time for average hair dryer use. Even in a house full of kids that may see a lot of hair dryer usage - each one only uses for maybe 10 minutes max or at least about that long before cycling it for whatever reason.

What gets you into trouble is more then one hair dryer on same circuit or maybe a portable space heater is being used on same circuit, that is when you are getting near 30 amps of load with heating loads alone, but still may surprised how long 20 amp breaker will hold before first trip. But also consider that if adding an extra 1500 - 1800 watts of heat to the room via the hair dryer, the portable heater may not be calling for heat as the room will warm up fast.

 

[James L]

Not by code for a dwelling unit. There is no NEC value for a dwelling unit receptacle.


That is a fine choice but again not set by the code.

The OP did not ask what is the skimpiest code requirement for some lazy tightwad to adhere to, he asked....what do you do?

And in an unknowable scenario, that's how I do it - 180va per receptacle for general use. Typically I put 8-10 receptacles on a 15amp circuit.

 

[templdl]

12x60W= 780W, which is 6.5A. A 1800W hair dryer (some are 1950-2000W) is 15A. That's 21.5A on a circuit, *IF* the HO doesnt lamp the vanities with 75 or100W bulbs. If s/he does the latter, that's 10A (12 100W bulbs) + fart fans (minimal load) + recessed lights (again, minimal load) + hairdryer (1800+W; 15A). That's 25A+ on a 15 or 20A breaker (assuming nothing on the upstairs bathrooms). I would hope the breaker would trip in <3 hours with that load. Hair dryers can run for 20min or more...

Now, if they use 40W incandescent (or 25W) or fluorescent or LED, there wont likely be a problem. But on a three-quarter million dollar home, I would prefer there be no chance of problems.

I may depends upon how the guy that that ritch to afford the home. If they are penny pinchers it may come down to the lowest bid being anal about what they get is what they paid for.
Personally adding more outlets on a wall often does not add tha much more cost. It is much easier to reach an outlet placing less stress on cords being closer together and less need for power strips. Adding extra circuits does often a cost but does assure more reliability by providing less of a chance to trip a breaker.
By providing the bare minimum as required by the NEC it iis the best way to assure a competitive bid and get the job. But soulkd you bond with the owner on selling them of the benefits of you expert input they may feel more comfortable with you doing the work in their best interest.

 

[iwire]

The OP did not ask what is the skimpiest code requirement for some lazy tightwad to adhere to, he asked....what do you do?

Its all good, I was just pointing out it was not a code restriction.

I can't tell you how many 20 amp circuits I run that I know will have less than 5 amps of load.

 

[mbrooke]

Its all good, I was just pointing out it was not a code restriction.

I can't tell you how many 20 amp circuits I run that I know will have less than 5 amps of load.

That is unless you have women in the home :thumbsup:

 

[kwired]

The OP did not ask what is the skimpiest code requirement for some lazy tightwad to adhere to, he asked....what do you do?

And in an unknowable scenario, that's how I do it - 180va per receptacle for general use. Typically I put 8-10 receptacles on a 15amp circuit.

I generally take the use of the area into consideration, and even in non dwellings I may do this but do need to watch out for the inspector that may get hung on the 180VA per outlet.

Take a typical bedroom - what is normally there for load? Outside of an older home with poor heating system or no central cooling often you never see more then 3-5 amps of load for the entire room, or if there is more load then that it is for fairly short duration, like the occasional vacuum cleaner for a few minutes.

Doesn't matter if you have absolute code minimum of one outlet ever 12 feet or wall or if you have one outlet every two feet - the load for the room is still the same, they will just use more extension cords/power strips/triple taps/etc. in the room with less outlets.

I often run 15 amp circuits for the lighting (to multiple rooms) and 20 amp circuits to the receptacles (to multiple rooms). For the lighting I generally try to go by the VA of the intended luminaires, maybe allow some wiggle room for unknowns or future, and in more recent years you can get away with even more outlets as the incandescent lamp is vanishing for more efficient replacements. The receptacles - I have often put 3 or 4 bedrooms on one 20 amp circuit regardless of how many receptacle outlets may be installed - never have any call backs for overloaded circuits.

 

[templdl]

If I may spice this up a bit, I haven't actually measures the current spikes from a high wattage audiophile sound system but current spikes required to drive base sound would translate to corresponding voltage drops. If so, may the common 15a circuit w/#14 wire be marginal evern rthaugh the actu as l load may be well within ithe rating? For a commercial sound system using 3 pr 4 500 and 1000w amplifiers we specified that #10 wire be used for the 20a ckt for a 100'rt in from the panel to assure that the voltage was stiffer.just based inon the current spike that we anticipated.

 

[kwired]

If I may spice this up a bit, I haven't actually measures the current spikes from a high wattage audiophile sound system but current spikes required to drive base sound would translate to corresponding voltage drops. If so, may the common 15a circuit w/#14 wire be marginal evern rthaugh the actu as l load may be well within ithe rating? For a commercial sound system using 3 pr 4 500 and 1000w amplifiers we specified that #10 wire be used for the 20a ckt for a 100'rt in from the panel to assure that the voltage was stiffer.just based inon the current spike that we anticipated.

I guess that is spicing it up a bit, how often do you run into a sound amplifier with that kind of output capacity in a dwelling?

Even in the commercial application - it may be NEC compliant to put it on the 15 amp circuit, but is still good design practice to ensure it has no other load on same circuit to impact the performance as well as provide circuit conductors sized to eliminate the voltage drop issues if they present a performance issue - you could still use a 15 amp circuit breaker even if you ran 8AWG circuit conductors for voltage drop purposes.

 

[mbrooke]

I generally take the use of the area into consideration, and even in non dwellings I may do this but do need to watch out for the inspector that may get hung on the 180VA per outlet.

Take a typical bedroom - what is normally there for load? Outside of an older home with poor heating system or no central cooling often you never see more then 3-5 amps of load for the entire room, or if there is more load then that it is for fairly short duration, like the occasional vacuum cleaner for a few minutes.

Doesn't matter if you have absolute code minimum of one outlet ever 12 feet or wall or if you have one outlet every two feet - the load for the room is still the same, they will just use more extension cords/power strips/triple taps/etc. in the room with less outlets.

I often run 15 amp circuits for the lighting (to multiple rooms) and 20 amp circuits to the receptacles (to multiple rooms). For the lighting I generally try to go by the VA of the intended luminaires, maybe allow some wiggle room for unknowns or future, and in more recent years you can get away with even more outlets as the incandescent lamp is vanishing for more efficient replacements. The receptacles - I have often put 3 or 4 bedrooms on one 20 amp circuit regardless of how many receptacle outlets may be installed - never have any call backs for overloaded circuits.

Ive done 14/3 split wire in homes Ive lived in

 

[templdl]

That is unless you have women in the home :thumbsup:

Yes, just how many Nesco roasters, coffee pots, wormers, hot plates can she get on a circuit for a Thanksgiving, Chistmas, New Years day, Superbowl party, birthdsay party, family get together, circuits that normally may see a 5aaa at most.
Not enough plugs, cord not long enough? Just grab that 16gage l amp extension cord she keeps in the kitchen drawer which will do.

 

[templdl]

I guess that is spicing it up a bit, how often do you run into a sound amplifier with that kind of output capacity in a dwelling?

Even in the commercial application - it may be NEC compliant to put it on the 15 amp circuit, but is still good design practice to ensure it has no other load on same circuit to impact the performance as well as provide circuit conductors sized to eliminate the voltage drop issues if they present a performance issue - you could still use a 15 amp circuit breaker even if you ran 8AWG circuit conductors for voltage drop purposes.

What it often boils down to is the opportunity to do and -B side by side comparison of two identical sound systems supplies differently and the just isn't going to happen. My observations were based upon theory and the brief high current spikes to drive the bass. You would have that have some sophisticated measuring devices cause the voltage to take a dive.
Without a side by side comparison the benefit of having a larger supply conductor would not be noticed.
It is all relative.

 

[kwired]

What it often boils down to is the opportunity to do and -B side by side comparison of two identical sound systems supplies differently and the just isn't going to happen. My observations were based upon theory and the brief high current spikes to drive the bass. You would have that have some sophisticated measuring devices cause the voltage to take a dive.
Without a side by side comparison the benefit of having a larger supply conductor would not be noticed.
It is all relative.

Some serious audiophiles can tell if you are using oxygen free cable without side by side comparison though