90's in pipe run, also underground pvc

[boyle78]

I was told recently that a pipe run was allowed to have more than 4 90's if the pipe run was sized significantly larger than what you needed (i.e. 1.25" emt for 3 #12 thhn). According to the master, California allows this practice, yet he could not show any written proof to support his claim. I was in the understanding that code states no more than 360 degrees in a pipe run...regardless of size.
Another question I have is if expansion fittings are required in the ground when running pvc (sch40 or 80) ? I now if the pipe is exposed to temp changes like when being run on rooftops, exterior walls, ect.
If anyone could shed some light on these two questions, I would apprectiate it greatly.

 

[roger]

If you are installing per the NEC your master is wrong.

Roger

 

[acrwc10]

342.26 Bends ? Number in One Run.
There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.


There is no exception following this one.

 

[boyle78]

hey stated "they" as in AHJ allowed him to do so if he was running under a concrete slab....i really think he is "full of it". If your in CA or NH, code os code to me.

 

[celtic]

hey stated "they" as in AHJ allowed him to do so if he was running under a concrete slab....

I did not see a "they" in the OP.

In any event....you have to ask yourself WHY only 360??


In regards to expansions underground, see:
300.5(J)
352.44

 

[stickboy1375]

In any event....you have to ask yourself WHY only 360??

Gotta stop somewhere, 360 sounds pretty darn good to me...

 

[celtic]

Gotta stop somewhere, 360 sounds pretty darn good to me...

I was thinking (ok hoping ) some smartazz would say:
Well, if the limit was 180?, you'd be pulling the wires out just as quickly as you pulled them in. LOL


....that's not the answer I was looking for Stickboy....try again?

 

[mdshunk]

That four quarter bends rule has been in the NEC for pretty much the entire history of electrical raceways.

 

[acrwc10]

hey stated "they" as in AHJ allowed him to do so if he was running under a concrete slab....i really think he is "full of it". If your in CA or NH, code os code to me.

I am in California and the limit is still 360 degrees "if anyone is counting"

"220-221 what ever it takes."

 

[infinity]

We have some POCO's that limit the number of bends to 180 degrees for underground service laterals along with large radius elbows.

 

[Jim W in Tampa]

You can pull wire thru more than 360 but its not legal.Sometimes we put a box in line with straight run to simply make it legal but pull right thru it anyways.Over size makes it easy and a pull box keeps it legal.Anyone ever add in all them small angles pvc makes even on straight run ?

 

[iwire]

You can pull wire thru more than 360 but its not legal.Sometimes we put a box in line with straight run to simply make it legal but pull right thru it anyways.

Jim we do this all the time.

Where do you find that it is 'illegal'?

 

[infinity]

Jim we do this all the time.

Where do you find that it is 'illegal'?

I think that he's saying it's not legal to pull through more than 360 degrees. I don't believe that it says that in the NEC. It only says you need pull points with not more than 360 degrees between them. It's up to you as to whether or not you choose to use them.

 

[Jim W in Tampa]

I think that he's saying it's not legal to pull through more than 360 degrees. I don't believe that it says that in the NEC. It only says you need pull points with not more than 360 degrees between them. It's up to you as to whether or not you choose to use them.

Sort of proves nec made up a crazy number doesnt it ?

 

[Rockyd]

Sort of proves nec made up a crazy number doesnt it ?

Not really.

Back in the 80's when Portland, Oregon's apprenticeship school was located over on Killingsworth they had an interesting exercise....

They had a run (1/2" EMT) with 7 90's in it. The apprentices had to pull three number 12's in it (dry). Was a good exercise in why not to put more than four 90's in a run. Thought it was a good emphasis on why we properly plan our pipe routing and try to make a reasonable opportunity for setting up our tugging gear at a reasonable spot.

If the decision was left to the field, wonder how many runs would fail a megger test?

Got to draw the line somewhere.

 

[Jim W in Tampa]

Not really.

Back in the 80's when Portland, Oregon's apprenticeship school was located over on Killingsworth they had an interesting exercise....

They had a run (1/2" EMT) with 7 90's in it. The apprentices had to pull three number 12's in it (dry). Was a good exercise in why not to put more than four 90's in a run. Thought it was a good emphasis on why we properly plan our pipe routing and try to make a reasonable opportunity for setting up our tugging gear at a reasonable spot.

If the decision was left to the field, wonder how many runs would fail a megger test?

Got to draw the line somewhere.

I agree there needs to be a number but 360 doesn't always make since.Given that same situation and make it stranded with lube and 1 inch emt it would proved nothing.Often all we need is another small kick or 45 and if run is short can push the wire.Just how was 360 picked and how was it tested ? Perhaps they simply wanted to sell more lb's and boxes.The code is not writen by people with no outside influance and they are paid.

 

[480sparky]

I agree there needs to be a number but 360 doesn't always make since.Given that same situation and make it stranded with lube and 1 inch emt it would proved nothing.Often all we need is another small kick or 45 and if run is short can push the wire.Just how was 360 picked and how was it tested ? Perhaps they simply wanted to sell more lb's and boxes.The code is not writen by people with no outside influance and they are paid.

I doubt any of those who came up with the 360? figure is still alive.

 

[masterinbama]

The wording alone tells me it's been in the code a long time. "No more than the equivelent of 4 quarter bends". As for pulling through more than 4 90's we do it all the time.We put in cee condulets in our runs to satisfy the NEC but pull straight through them. Especially if one of the 90's is at the very beginning of the run. With proper cable feeding ( IE pushing the cable) the first 90 doesn't really add to the pulling force

 

[Rockyd]

Jim,

Normally, when I consider a field electrical problem, I ask the following questions -

1) Is it conceptually possible?

2) Is it Safe?

3) Is it legal?

That said, I think most of all, have had to "stretch" a compass more than 360 degrees in our careers, and with due care, it was safe to do so.

Code panels are interesting groups. Take a look who sits on each one, and notice the make up of each -

Normally each will have a Committee Membership Certification.

The membership of each panel normally consists of a an Inspector representative (IAEI) A Manufacturing representative, a NECA representative, a couple of Contractor representatives, an IBEW representative, Schools of higher learning representatives, Safety experts, and other experts (IEEE for example). With all that horsepower though, they still put their pants on one leg at a time, and can still make mistakes. Chances are, they are sharp bunch on the average.

Looking here in a 2002 code book in History and Development of the National Electrical Code is the following verbage -

This Code is purely advisory as far as NFPA and ANSI are concerned but is offered for use in law and for regulatory purposes in the interest of life and property protection. Anyone noticing any errors should notify the Secretary of the National Electrical Code Committee at the NFPA Executive office.

So via the 10th amendment (U.S. Constitution), most states adopt the code as law. Wiggle room is allowed for critical thinking skills in 90-4, and in otherplaces in the code "engineered" also carrys a lot of weight. When no one is looking, you make the final call.

 

[iwire]

Sort of proves nec made up a crazy number doesnt it ?

No, not at all.

They just want to make sure you can get the wire in the pipe.

Have you tried to push a snake through more then four 90s?

I always ask my guys to make all pull boxes able to be pulled straight through so we have options. We can pull through it or to it depending on the situation.