2017 NEC Posted

[pv_n00b]

No print copies yet but the online copy is up on the NFPA website. Click "Free access to the 2017 edition online" to view it.

Read it and weep, or rejoice, as the mood strikes you.

 

[Smart $]

It appears 250.122(B) was not revised back to voltage drop only as we thought it was going to be...

(B) Increased in Size. Where ungrounded conductors are
increased in size from the minimum size that has sufficient
ampacity for the intended installation, wire-type equipment
grounding conductors, where installed, shall be increased in
size proportionately, according to the circular mil area of the
ungrounded conductors.

NO CHANGE from 2014.

At least 3 more years of ambiguity.

 

[rbalex]

I say the new online table of contents makes it much easier to navigate. Otherwise, it's still a PITA.

Section 501.15(E)(3) has had the missing "not" returned and it is easier to explain why certain cables aren't required to be sealed.

It stuns me that CMP 14 permits threadless couplings in Class I, Division 2. I guess the bonding paranoia has subsided a bit. [501.10(B)(1)]

The other Art 501 changes are negligible in my opinion.

 

[infinity]

I see that they rewrote 680.74 regarding hydromassage tubs to make them more like permanently installed pools.

 

[don_resqcapt19]

It appears 250.122(B) was not revised back to voltage drop only as we thought it was going to be...



NO CHANGE from 2014.

At least 3 more years of ambiguity.

The change was in the Second Draft Report, but was deleted by a vote of 179 to 138 on motion 70-7 at the June meeting.

 

[MasterTheNEC]

It appears 250.122(B) was not revised back to voltage drop only as we thought it was going to be...



NO CHANGE from 2014.

At least 3 more years of ambiguity.

It was actually on the NITMAM agenda as well in Las Vegas and it was argued vigorously but in the end the votes just did not carry it. The vast majority felt that any such increase should be considered and voltage drop was only one potential aspect. There are many possible situations that could result in increased conductors and the open members of the NITMAN could not agree to only limit it to voltage drop.

Just the messenger but it was debated and not by just panel members. It was open on the floor for the NFPA Conference attendees to vote as well.

 

[FionaZuppa]

2020 it will say "nec needs fixin? we fixed it"

 

[Smart $]

It was actually on the NITMAM agenda as well in Las Vegas and it was argued vigorously but in the end the votes just did not carry it. The vast majority felt that any such increase should be considered and voltage drop was only one potential aspect. There are many possible situations that could result in increased conductors and the open members of the NITMAN could not agree to only limit it to voltage drop.

Just the messenger but it was debated and not by just panel members. It was open on the floor for the NFPA Conference attendees to vote as well.

A majority opinion carries the vote regardless of correctness.

 

[mgookin]

NEC online access

NEC online access

FYI the default NFPA online access has rolled to the 2017 edition NFPA 70.

But there is a tab on the page which says "Current & Prior Editions" where you can select and view previous editions going back as far as 1993.

I just learned this so I thought others may want to know there are older code editions available online. Enjoy.

 

[MasterTheNEC]

In that view I guess so.

Comments based on the 2017 National Electrical Code.

 

[mgookin]

I hadn't read this thread and posted another thread at http://forums.mikeholt.com/showthread.php?t=178558
Mods: You can nuke that thread if you want.
The only material information in there is you can click a tab to view the older versions back to 1993.

 

[iwire]

I hadn't read this thread and posted another thread at http://forums.mikeholt.com/showthread.php?t=178558
Mods: You can nuke that thread if you want.
The only material information in there is you can click a tab to view the older versions back to 1993.

I think it was good of you to mention that the default is 2017 which for some folks may be many years before it applies.

 

[don_resqcapt19]

It was actually on the NITMAM agenda as well in Las Vegas and it was argued vigorously but in the end the votes just did not carry it. The vast majority felt that any such increase should be considered and voltage drop was only one potential aspect. There are many possible situations that could result in increased conductors and the open members of the NITMAN could not agree to only limit it to voltage drop.

Just the messenger but it was debated and not by just panel members. It was open on the floor for the NFPA Conference attendees to vote as well.

For those that are interested, you can get a cope of the motion debate transcript here. The NEC part starts on page 161.

 

[Carultch]

For those that are interested, you can get a cope of the motion debate transcript here. The NEC part starts on page 161.

I see they gave the misleading explanation that larger phase conductors somehow cause greater fault currents. There is a kernel of truth to this, in that greater conductor resistance/impedance reduces fault current, and therefore greater conductor size might seem to mean greater fault currents. However, the same result can happen with a shorter length circuit to begin with.

In any case, larger conductors do not increase available fault currents to any greater value than the available fault current already was, at the origin of the circuit.

 

[Smart $]

For those that are interested, you can get a cope of the motion debate transcript here. The NEC part starts on page 161.

I see the discussion about 250.122(B) starting on page 230.

 

[Smart $]

I see they gave the misleading explanation that larger phase conductors somehow cause greater fault currents. There is a kernel of truth to this, in that greater conductor resistance/impedance reduces fault current, and therefore greater conductor size might seem to mean greater fault currents. However, the same result can happen with a shorter length circuit to begin with.

In any case, larger conductors do not increase available fault currents to any greater value than the available fault current already was, at the origin of the circuit.

The thing they do not seem to realize is, the greater fault current actually causes the overcurrent device to trip quicker... :slaphead:

It was brought up that keeping the same size EGC would cause it to warm up more, anneal, and have less contact under the termination for the next time. The thing is is that the overcurrent device should trip well before the EGC ever gets close to annealing temperature to begin with.

I have no idea where some of these so-called industry experts get these ideas.... well I sort of do, but it seems no one is there to help them integrate (or not) the idea with the actual physics.