... I'm trying to size an indoor trough for the 300 amp service we're working on... I'd be coming into the top of the trough with a 3" pipe,and exiting through the bottom of the trough into (2)150 amp panels via (2)-2" nipples... My recollection is that since this will be a straight pull,I must go with 8 times the largest diameter pipe,which will give me a minimum of 24".. the other dimension large enough to accomodate lock-nuts...will a 24"X 8"X 8" trough be adequate?? my supply conductors will be 250kcmil copper..also I must bond this trough,as I'm using PVC nipples..what size bonding wire should I go with??
Russ

(edited to put image on the ECN server)

[This message has been edited by electure (edited 10-26-2005).]

Nice signal balloon.

I am having a hard time picturing your installation.

Are you planing on the trough being vertical or horizontal?

If you are planing on 8" x 8" being enough space to get two 3" raceways in I think that will be difficult. I would go 10" x 10".

Can you describe it a little more.

... The trough would be horizontal,with one 3" pipe entering through the "top" and two 2" pipes coming out the "bottom",each going into a 150 amp. CB panel, a typical service installation in a basement for a 300 amp service..
Russ

[This message has been edited by Attic Rat (edited 10-25-2005).]

Then it will have to be larger between the top and the bottom.

First it sounds to me like the angle pull rules apply as it sounds like the 3" will not line up with the 2 - 2" and I imagine you are splicing in the trough.


3" x 6 = 18"

or

2" x 6 + 2" = 12"

So the you need 18" minimum between the incoming 3" and the out going two - 2"

I don't think there is a cut and dried code answer to this, because the code doesn't define what a straight pull is and what an angle pull is.

Bob, I agree with your take, in calling this an angle pull, but I think that 376.23(B) applies only to the distance between the raceways. 376.23(A) applies to the physical size of the wireway, which would permit a very small wireway, if the raceways have enough space between them.

I have a change submitted to the 2008 to this section to try to clarify this (I would like to see a 30 degree deflection govern the rules).

[This message has been edited by Ryan_J (edited 10-25-2005).]

You lost me Ryan, if it has splices it is an angle pull that is cut and dry.

Also 376.23(B) only applies to raceways containing the same conductors. Assuming he is splicing 376.23(B) is not applicable.

Bob

I didn't see that he was splicing.

Are you splicing, AR?

He has one 3" incoming and two 2" outgoing.

My money is on a splice in the trough.

He may have run parallels in the same 3" but I doubt it as than you have derating issues.

My view is biased as I almost never run parallels for less than a 400 amp circuit.

Of course I am just a Hack so don't listen to me.

I was visualling (2) 150 amp breakers in the above panel, and main lugs on the bottom panel, you hack.

It's OK, I'm a hack too

It's a heck of a club.

At least your 'orientation' was not questioned.

LOL...Um...nevermind

If you guys are starting a club, how much are the dues? If its a hack club I think I should be a charter member!

Well...we're not quite sure who the voting comittee is yet.

Iwire-

I wish I could cut and paste a drawing here, but here goes...

If you had a box/raceway that is 7" tall x 24" wide x 6" deepand it has one 3" EMT coming in the left and one 3" EMT going out the right of the box, the top of each EMT being 1" from the top of the box, you would consider that a "Straght" pull.

Now, using the same box but having one EMT being 1' from the top of the box and the other EMT being 1' from the bottom of the box, would you consider that an "Angle" pull?

Hope this made sense.

Steve
[This message has been edited by skingusmc (edited 10-25-2005).]

[This message has been edited by skingusmc (edited 10-25-2005).]

... I'm sorry gentlemen,..I just got in,and checked this thread since the last time I posted this morning..

... Yes,Bob, you got it,..I intend to splice in the trough,250kcmil(300a.) to(2)-1/ "ought"(150a.) How do I make the symbol for "ought"??
Russ

If a hack like me was to use wireway Tee and Elbow fittings, then what would the result be?
Most wireway sections are marked with a maximum conductor size for conductors coming in the sides. This doesn't correspond at all with 314.28, but addresses wire bending space.

Steve I understand your description.

I am not sure of the answer, I think that was what Ryan is getting at.

Is a straight pull literally straight or just on opposite sides?

For what it is worth in my opinion a straight pull means that the raceways line up directly across from each other with no deflection of the conductors.

Any splice, deflection, change of direction etc. is an angle pull.

Scott I am not sure, I certainly have seen sets of 600 Kcmill enter the top of a 12" x 12" trough but I doubt it meets code.

The company I work for is more concerned with progress and passing inspection than worrying about the cost difference between an 18" x 18" can or a 24" x 24" can so I tend to figure big most times.

I also try to plan my pipe runs in a way that I can use trough the long direction as a required pull point. I typically will use a 6" x 6" x 48" trough with 4" raceways.

Attic Rat

How about you place a 12" x 12" x 18" trough vertically between the panels. Enter the 3" in the top and come out each side with your 2" into the side of each panel?

3" x 6 = 18"

2" x 6 = 12"


Bob

Hey, I think I might be a member of that club too.

Roger

My ideas are as follows. Enter a vertical section of wireway and place a tee fitting at the bottom. Any way you want to turn it is fine. You could save 1 elbow by turning it so that 1 set of conductors will pass straight through to 1 of the panels.

The other set would go out of the tee and into a short section of wireway. You could either use a wireway elbow or a conduit elbow to come down into the other panel (Take your choice).

Totally compliant, isn't it?
(not too bad for a hacker )

... Guys,guys,guys... I remedied my own problem today whilst talking to my inspector..

... It's really quite simple,and I was probably over-thinking it as usual..
I just run my 3" pipe underground and up to the meter pan,then once there,come off the load side of the meter with parallel lugs with my 1/0 wires thru (2)-2" LBs,and one each into my (2)-150 amp main breaker panels below in the basement..VOILA!! the trick she is done...and it'll pass cuz the AHJ said I could do it that way...No trough,no bugging. Thanx for all your help tho',..you guys are terrific
Russ

[This message has been edited by Attic Rat (edited 10-26-2005).]

Sorry, I didn't realize that I wasn't a qualified hack.
I don't go to the place that the "hackusations" were made. I heard the story last night.
I thought maybe I was a hack on my own lack of merit.

Scott I will welcome you to the hack club if you want.

Personally I think it is good company.

Roger, Ryan, CTwireman, myself and now you.

None of us know or care at all about the NEC or the trade in general.

Bob

Thanks a million, Bob!!

I always knew that the general lack of compassion for fellow electricians, disdain of the NEC, and dislike of the electrical trade would pay off.

I'm among friends!! I'm a HACK!!

For the first HACK CLUB meeting, we are going to learn the proper techniques for sharpening our axes and chainsaws. It's been said that some members are not sharpening properly, and thus are not hacking up to their full potential.

Also, we will learn how to better mix the 50-50 oil and gasoline for optimum chainsaw efficiency. If it's cold, we will be burning our copies of the NEC and EC&M magazine in the woodstove.

-Peter, another proud Hack

Can a lowly cinema tech join the hack club too?

... Jeez Louise,... Look what I started,... I guess I'm running for trea$urer of this club..any objections??
Ru$$

... Here's what it looks like outside..

That expansion fitting for frost heave is a good job. Did you forget the fitting for the smaller PVC, or was that there already?

... No, my helper got a little "ambitious" and went ahead and started the 1-1/2" run without me..he forgot the expansion coupling..he had it all glued together by the time I got to the site,I called the AHJ,and told him about it,and that it's only for Cable TV,and Telephone,and he said he wouldn't knock it down so long as the coupling was there for the 3" pipe.. I personally installed the one on the 3" pipe..I'm still stewing over redo-ing the 1-1/2" LB,anyway, and adding the expansion coupling there as well..I probably will,as there's no wire in the pipe ...yet..
Russ

Russ, brought up a good issue here, he may have solved his problem, but i see many under sized raceways out there, as Bob said, "The company I work for is more concerned with progress and passing inspection than worrying about the cost difference between an 18" x 18" can or a 24" x 24" can so I tend to figure big most times."

Working with larger conductors in a small raceway can be tough, but i still see many undersized raceways out there, i can't see the savings, when what you save on the box costs you 4 times over in labor.