15A/ 20A circuit load question

[celtic]

No matter how you slice it - at some point a minimum must be established.

What one person feels is "minimum", another may view as "below minimum".

In the case of home, we NO idea what will be plugged in where. We can "assume" certain areas are likely to have a higher demand than other areas (bth, kit, etc)...but we don't know.

With the human variable so dynamic, how can a "minimum" be set that will be acceptable to all?

 

[peter d]

With the human variable so dynamic, how can a "minimum" be set that will be acceptable to all?

I think the NEC has already done a good job of it. If you actually look at the real numbers, the code allowances are way on the conservative side.

Why does a 200 amp service get 1/0 underground conductors or #6 over head conductors from the poco? Because they have the load requirements down to a science and they know that the NEC factors in overkill.

 

[Mike03a3]

i don't know why people have the impression that every recep in a house is going to be loaded down. think about what you're actually using in your own home. we use 3 receps in my living room. one for the tv, one for the computer in a corner, and one for a lamp. bedroom, one for an alarm clock, one for a lamp, and one for a tv. these aren't mini-factories. the loads are going to be minimal. in a 1200 sq. ft. house i would typically have one circuit for all gen. receps, two lighting circuits, and two bedroom circuits + sabc's. that gen. purpose recep circuit will have maybe 13-15 receps @ 1200 sq. ft.

You aren't supporting the economy . . .

Rec room: TV corner: TV, Cable box, DVD, VCR, 8mm VCR; Stereo corner: Receiver, Power AMP, CD changer, Cassette player, Reel-to-Reel tape, Record changer [yeah, ok, so maybe some of it is old, but I've go a lot of old media]; misc: three lamps, phone wall wart, answering machine wall wart.

Computer room (third Bedroom): Closet light, two lamps, desk light, computer, monitor, external SCSI CD changer, scanner, laser printer, photo printer, inkjet printer, USB hub, UPS, internet cable box, wireless router, network switch, phone wall wart, battery chargers for GPS, two digital cameras.

Second bedroom (when my daughter still occupied it): TV, cable box, phone wall wart, stereo, vcr, dvd, nintendo, computer, scanner, printer, usb hub, ups, clock radio, several battery chargers

Master bedroom suite is practically empty: 4 lamps, sewing machine, clock radio, TV, two closet lights, one hall light (the "hall" being the space between the bedroom and bath, with a closet on each side) one vanity light (three bulbs), plus two overhead and a six bulb vanity in the bathroom.

Then there's the foyer, one and a half baths, laundry room, fourth bedroom, living room, dining room & kitchen.

Yeah, it's more than 1200 square feet. More like 3600. But my daughter's house isn't and she's got it packed with technology. It's a far cry from my parent's day when a 60 amp service was overkill because they owned almost no electrical appliances and gadgets.

 

[LarryFine]

. . . external SCSI CD changer . . .

Sounds like a Mac user to me. Still using a Performa?

 

[Hassel4]

15amp to go

15amp to go

NEC Article 220.3 (B)(9) does not give a guidline on the number of outlets on a 15 or 20 amp circuit?

I agree that 15a should go. No, we are not going to rip it out of existing circuits. I just think the way we live today is not suited for 14ga. I also know of situations where homeowners replace outlets with three prong so they can use that larger load. I say play it safe, run 20a.

 

[iwire]

I agree that 15a should go. No, we are not going to rip it out of existing circuits. I just think the way we live today is not suited for 14ga.

You can deliver just as much total power to a home using 14, just run more circuits.

I also know of situations where homeowners replace outlets with three prong so they can use that larger load.

What does a three prong outlet have to do with the load on the outlet?

I say play it safe, run 20a.

What is unsafe about 14 AWG with a 15 amp breaker?

 

[electricmanscott]

NEC Article 220.3 (B)(9) does not give a guidline on the number of outlets on a 15 or 20 amp circuit?

I agree that 15a should go. No, we are not going to rip it out of existing circuits. I just think the way we live today is not suited for 14ga. I also know of situations where homeowners replace outlets with three prong so they can use that larger load. I say play it safe, run 20a.

This is just an ignorant statement. The facts are what they are. Millions of home with 14 ga wire and 15 amp circuits, and they are fine.


I'll be nice since this is your first post, but the "three prong outlet" comment is very telling.

 

[mauk]

I have only done larger upscale homes so far (7000+ sq. ft, $2M+), but we typically err on the side of caution. I do not want to get that call from a homeowner or their rep. complaining of a poor design.



For what it's worth, I've caused a pretty large amount of nuisance trips with my computer and stereo system . It can be rather annoying at times. Electronic devices are getting more and more power hungry.

 

[Mike03a3]

Sounds like a Mac user to me. Still using a Performa?

No, just have a SCSI CD changer on an old HP PC. That room is like a micro computer museum - I just listed the things that were plugged in and being used. There are at least eight computers in there. The changer is probably on its third or fourth system.

 

[Mike03a3]

Electronic devices are getting more and more power hungry.

Thanks to Energy Star and other programs, most devices probably aren't. The real problem, IMHO, is the number of things we plug in.

Back when I was in high school, just before the meteor wiped out the dinosaurs, my parent's home had a very minimal electrical footprint.

The kitchen was the big energy hog, with an electric range and refrigerator. But the ONLY other electric appliances my mom had were a mixer and a toaster. No dishwasher, no electric can opener, no disposal. Nothing. The basement had a washing machine - the dryer was called a clothesline and was installed in the backyard.

The gas furnace had a blower motor; the living room had a TV/Radio/Record Player console, mom had a sewing machine & iron and I had a Dynakit stereo I built (four pieces: tuner, pre-amp, amp & a turntable).

The only powered tools were an electric drill and a soldering iron.

That's it. Other than a few lamps, that is the entire list of things that plugged in. For a three bedroom house with full basement.

Contrast that to all the gadgets we have in our modern lives. One of the biggest problems we have at our house is lack of receptacles. All the wall warts for phones, battery chargers, etc, etc. need a place. Even the cameras have battery chargers these days.

Yes, I realize we aren't typical in some ways - I'm an electrical engineer with a predisposition to accumulate gadgets, plus I'm old - so have many years accumulation. But I don't have to look farther than my daughter to see the depth and breadth of electrical stuff that has somehow become essential.

The NEC is a reflection of a reasonable attempt at a minimum. The requirement for two SABCs reflects the difference between my mom's kitchen and mine, as does the need for things like a 20A circuit to the bathroom. My mom didn't need one, she didn't have a hair drier.

But it is a minimum. I am in favor of more circuits and 20 amp receptacle circuits and denser spacing, to reflect the need for more place to plug in all the accoutrements of modern technology and the higher power demands. HOWEVER, that's a design decision. And it's one that, I'm sure, reflects my myopic view based on living and working in an area that is both high-tech and relatively affluent. And because I know it's myopic, I certainly wouldn't claim the minimum needs to be raised. We just all need to be cognizant of the realities of modern life in our designs and recommendations.

 

[Mike03a3]

All the wall warts for phones, battery chargers, etc, etc. need a place. Even the cameras have battery chargers these days.

Speaking of wall warts, have you noticed they almost all are designed for receptacles with the ground down? :grin: