Amount of outlets per breaker

Christopher_amatulli · #1 Oct 30, 2007, 07:43 AM

just trying to find the standard codes for the # of outlets for each breaker for the typical amperage...

15 amp 110 volt
20 amp 110 volt
30 amp 110 volt

Christopher_amatulli · Oct 30, 2007, 08:28 AM

according to the building department their is a maximum number of outlets per the eletrical code based on the amps for each outlet and that i should refer to an eletrican or the eletrical code to get that number.

as an example, in a residential home to meet both building codes and fire codes they list a max of 12 outlets per 15 amp breaker

strongbase · Oct 31, 2007, 08:25 AM

referring to the previous answer and additional:
1. i am in slight disagreement with the above numer of outlets allowed by the book - in this area it is 8 because the max 80% load factor is enforced both residential & comml/indust - so 80% of 15a is 12a - converting to watts (12 x 120 = 1440) and thus 1440 divided by 180 = 8 - however many municipalities modify the code requirements (unfortunately) as indicated above
2. also note that the 180 number is only to be used if the actual load is unknown - otherwise you must use the actual total known connected load + the number of unknowns x 180 - the total again may not exceed the 80% max load

using this factor is done to reduce heating in the panel and conductors, rg

strongbase · Oct 31, 2007, 09:29 AM

Yes - exactly true and i did note that - however - i was referring to the maximum permitted load on the overcurrent device which is 80% After the derating for continuous loads - dont have time to look up the code section but to the best of my knowledge only some specially rated service switchgear is allowed to run at 100% load - this typically would not include common thermal magnetic trip CB's .. true ??? <grins> at any rate in this area for the past 30 some yrs it has always been 80% and we have to submit load calcs on all dwgs to prove this out for permit, rg (might be in 210.19 someplace) take care rg

tkrussell · Oct 31, 2007, 01:17 PM

210.19 is only for conductors.

The 80% rule for overcurrent protection now relies on 219.19 for the 80% only on continuous load, and is in line with the UL wording for breakers.

Much to the chagrin of us oldtimers, the 80% rule was re-written a few cycles ago. What with so many of us that used it for years, and so many of us do only commercial and industrial where everything can be considered to operate more than 3 hours, it is ingrained in us.

For residential, and considering the 180 VA is only for quantity of outlets on a circuit, I see no issue with allowing the counts I stated.

I try not to treat DIY'ers with disrespect, but they are ignorant to to huge amount of detail involved with this trade, and I like to deliver the best, simplest, and accurate info as possible.

strongbase · Oct 31, 2007, 03:22 PM

Quote:

Originally Posted by tkrussell

210.19 is only for conductors.

The 80% rule for overcurrent protection now relies on 219.19 for the 80% only on continuous load, and is in line with the UL wording for breakers.

Much to the chagrin of us oldtimers, the 80% rule was re-written a few cycles ago. What with so many of us that used it for years, and so many of us do only commercial and industrial where everything can be considered to operate more than 3 hours, it is ingrained in us.

For residential, and considering the 180 VA is only for quantity of outlets on a circuit, I see no issue with allowing the counts I stated.

I try not to treat DIY'ers with disrespect, but they are ignorant to to huge amount of detail involved with this trade, and I like to deliver the best, simplest, and accurate info as possible.

>>
First of all i must say i enjoy the technical dialog (with you) immensley - these types discussion are a great base for learning and it is always nice, valuable, and important to to get another's technical opinion - also of interest is the difference in the applicatin of the code in other areas of the country - although as i have travelled around in the course of my work it sometimes "bites" me <grins> ... also peer review is a most critical aspect of valid technical info as im sure you are well aware and technical 'disagreements' are even more important to ensure one's complete and accurate grasp of the subject (facts) - a great and fun learning experience that i never tire of - kind of like the search for the absolute truth as a professor indicated to me somewhat unkindly many years ago lol ... never forgot that .. also your time and interest and feedback much appreciated >>also note - i suppose we should take this type of dialog off the board so as not to consume resources (or is there a discussion area??) - feel free to email me [email address]

- tele might even be fun too on occasion (i am from the east coast originally) - spent part of my service time at Ft Devens actually ... anyway ... on to your reply

>re 210.19 - ahh yes entirely correct - as i realized shortly after i sent it - duh - i should have just left it at "i dont remember lol"

>re 80% rule - yes indeed - although again i was only refering to the loading of the OCD - i think labman referred to this recently too as i was browsing around (ill try to find it)
>number of outlets issue - yes - i see no real (or critcal) issue here either just a difference of area application perhaps and/or conservative design - i to am involved mainly in heavy industrial power distribution and some comercial and the 80% is in fact ingrained as you put it ... although again in this area - being a house or a 3000A service 80% and 8 outlets it is - most of cook county has very restrictive code application ...
>re DIY'ers .. ohhh yesssss .. some of the questions i see here are absolutely frightening and again kudos to you for taking to time to answer so many of them - i wish i had more - usually just brows and read but had some time today for a change to answer ... also it loooks to me like you do infact provide valuable technical help indeed and i surely hope that it is heeded - i see many receipes for disaster on here ...

>thats it for now - thanks again - and do consider contacting me directly ... take care, rg

tkrussell · Oct 31, 2007, 08:14 PM

So noted, take your time, read the questions carefully, and simply answer the questions with a fair, practical, and accurate answer.

I have often thought about having a technical post for those that enjoy the detailed aspect of this trade. There is no other than here for electrical. Any time you have any topic you would like to discuss, post it. Mark it for professionals, and there are several electricians here that I believe would like to join in with a discussion using our everyday lingo, and not have to explain every minute detail.

As far as the phone, I don't mind, but the better part of my job is on the phone, and I am not a talker, if you can believe that. Once I am home I don't even answer the phone.



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