ECN Forum Forums Code Related Discussion NEC & other Code issues 14/2 on switch loops

Mustang, exactly, and why is overfusing a #14 anymore dangerous than overfusing a larger conductor?

As far as John, is correct that this can and is probably with in code.

For example using a motor load.

#12 THHN for a 3 HP 1 phase 230 v All parts and conductors rated 75 deg

Article 430.148 3 HP = 17 amps

430.22(A) requires conductors be sized at 125 % of FLA

17 x 125% = 21.25 amps

Table 310.16, #12 @ 75 deg column = 25 amps

Table 430.52 allows up to 250% for inverse time breaker

17 x 250% = 42.5 amps

240.4 states we can go up to the next STANDARD size breaker = 45 amp breaker

Roger



[This message has been edited by Roger (edited 09-10-2004).]

electricman,
thanks for the reply. when i run across an installation like this i always look at the name plate..90% of the time the nameplate will indicate the LARGEST SIZE OCPD recommended and 90% of the time the breaker will exceed this..

example...

a 20 year old home gets a new condenser unit, the company that sells that unit will install a new disco but will NOT refeed the unit with the proper conductors...so they just pop in a 40 or 50a brkr and call it good..surely there are other folks out there who have run across this senario?

-regards

mustang

roger,
i don't know who John is but the topic was 14/2 on switch legs..not how many articles there are on OCPD that are allowed to exceed the current carrying capacity of a conductor..i see your point though..

my point was that it is VERY common and being allowed on current inspections..

and the argument that it is just good practice to provide some room for expansion on circuits, panels etc..

you wouldnt want to sell a customer a 32 ckt panel and then fill it up would you?

thanks for the replies..

mustang

Mustang, sorry, John is Electricman2.

The answer to 14/2 allowed on a 20 amp branch circuit is as already stated, "no" and along with Ryans reference of 240.4(D), the articles pointed to in 240.4(E) are pertinent.

As far as the thread not staying on topic, if you go back and read the posts, you will see it was drifting before I posted, and you will also notice my posts were addressing points or statements that were coming up.

BTW there was only one article that allows it in my post.

Roger

roger,
thanks for your input.

-regards

mustang

Mustang
Sorry if I may have led the thread astray. However my comment was meant to point out that sometimes what may seem to be a violation may not be. I applaud you however for being so conscientious in your work. I do agree that when running receptacle circuits, why use 14 when it costs no more in labor to use 12. The extra capacity is well worth the penny or so per foot.

[This message has been edited by electricman2 (edited 09-10-2004).]