Undergrounds 5000 Amp service - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


Like Tree10Likes
  • 1 Post By glen1971
  • 2 Post By telsa
  • 1 Post By Big John
  • 3 Post By Cow
  • 2 Post By ElectricArmy
  • 1 Post By ponyboy
Reply
 
Thread Tools Display Modes
Old 04-30-2017, 08:08 PM   #1
Junior Member
 
Join Date: May 2015
Location: East Brunswick New Jersey
Posts: 23
Rewards Points: 6
Default Undergrounds 5000 Amp service

I have to build the undergrounds for the afore-mentioned service soon. But I am looking for suggestions as to how to support all the 4" PVC's and keep them together and am wondering what other people have done.

5000 amp 480 volt service.

Two 5" primary's from pole to utility switch.

One 5" primary from switch to transformer 1.

One 5" primary from switch to transformer 2.

From each transformer, 7 4" secondary's to a giant, pad-mounted CT, and then from the CT, 14 secondary's to the building.

It is a strange setup because it is a building with an existing 3000 amp service, so we are upgrading to 5000 amp by re-feeding the existing gear and adding a new 2000 amp gear next to it, hence the pad-mounted CT I think.

But my question is for the large pit they opened up in which to install all the pipe for the pads: how best to stack, support, keep from tipping over, etc, the pipes? What kind of stakes and racks do you use? How do you keep it all plumb?

The CT window opening is barely big enough for 28 4" PVC conduits, so I cannot use strut for it. The opening is 28" x 36".
ElectricArmy is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 04-30-2017, 08:41 PM   #2
Senior Member
 
Join Date: Oct 2012
Location: Alberta Rockies
Posts: 2,716
Rewards Points: 3,790
Default

Use chairs and spacers for the horizontal runs.. Lots of scrap conduit pounded in to help keep everything straight and supported.. Gonna have to tighten up the spacing on the vertical into the entry.

Post some pics during your install!!
brian john likes this.
glen1971 is offline   Reply With Quote
Old 04-30-2017, 08:48 PM   #3
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,635
Rewards Points: 16,782
Default

I am on same page as Glen as he posted on that.

Plenty chair and spacers but make sure you do tie it down good to the ground espcally if you going cover up with a slab of cement. ( some area will required a slab of cement for this purpose)

5000 amp service is heckva a good sized service.

Yes tighten up the spacing on the conduits in the current transfomer cabent otherwise you may have to make some kind of base to changeover the size.

Dont be suprised in case your inspector will ask for concrete encased primary conduit run so kinda prepare for that.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 04-30-2017, 08:59 PM   #4
Senior Member
 
Join Date: May 2015
Location: Sacramento, California
Posts: 13,824
Rewards Points: 25,894
Default

Quote:
Originally Posted by ElectricArmy View Post
I have to build the undergrounds for the afore-mentioned service soon. But I am looking for suggestions as to how to support all the 4" PVC's and keep them together and am wondering what other people have done.

5000 amp 480 volt service.

Two 5" primary's from pole to utility switch. [ ie Poco @ distribution voltage ]

{ Watch out: my Poco wants 6" as a minimum for such raceways -- and spec's the sweeps, too. You are not permitted to use what suits you. Tight nineties are rejected. It's common for your sweeps to be slurried// concreted in. }

One 5" primary from switch to transformer 1.

One 5" primary from switch to transformer 2.

From each transformer, 7 4" secondary's to a giant, pad-mounted CT, and then from the CT, 14 secondary's to the building.

{ My Poco insists on 8 secondary pipes -- even if they intend to only use 3 out of the eight. They have their standards, the NEC has its. }

It is a strange setup because it is a building with an existing 3000 amp service, so we are upgrading to 5000 amp by re-feeding the existing gear and adding a new 2000 amp gear next to it, hence the pad-mounted CT I think.

But my question is for the large pit they opened up in which to install all the pipe for the pads: how best to stack, support, keep from tipping over, etc, the pipes? What kind of stakes and racks do you use? How do you keep it all plumb?

The CT window opening is barely big enough for 28 4" PVC conduits, so I cannot use strut for it. The opening is 28" x 36".
I don't comprehend your last sentence.
frenchelectrican and glen1971 like this.
telsa is online now   Reply With Quote
Old 04-30-2017, 09:18 PM   #5
Donuts > Fried Eggs
 
Big John's Avatar
 
Join Date: May 2010
Location: Portland
Posts: 17,054
Rewards Points: 300
Default

I just want to see a picture of this CT. Sounds like a single giant donut? Is it zero sequence for ground fault?

Seems really strange, never heard of anyone doing a standalone "padmount" CT like that.
Southeast Power likes this.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Always wear your gloves.
Big John is offline   Reply With Quote
Old 04-30-2017, 09:23 PM   #6
Junior Member
 
Join Date: May 2015
Location: East Brunswick New Jersey
Posts: 23
Rewards Points: 6
Default

So I have 7 secondary's from each transformer that have to be stubbed up into the bottom of the CT (14), and 14 conduits that have to go to the building. That it is 28 4" PVC's that have to be stubbed up into the bottom of the CT whose opeing for conduits is only that big - 28" x 36". My boss calls that opening a window. And that opening is rather tight for that number of conduits.

And yeah my poco has us using large radius sweeps as well, but there is no minimum spacing requirement or minimum number of conduit's required.

Also they don't need the primary's to be concrete encased.

And yeah all those ideas I have as well, the chairs and spacers and poles in the ground along with tie wire if need be.

We will see how it goes! Thanks!
ElectricArmy is offline   Reply With Quote
Old 04-30-2017, 09:26 PM   #7
Cow
Senior Member
 
Join Date: Jan 2008
Location: Eastern Oregon
Posts: 2,881
Rewards Points: 4,598
Default

You'll have to get creative. Here's how we did a 2000 amp service with a generator to give you some ideas. The six 4" 90'ed up over the top of the other conduits at an angle had to fit in the generator with only 1" of room around the outsides so it was tight.

We used stringlines to verify the angled conduits were stubbed up parallel to the building. We used T&B conduit spacers on everything except at the generator end, we had to squeeze all the conduits in right next to each other as you can see in the pics.

You could make a plywood or HDPE template to make sure your spacing is right for the CT window. We'll often times build the openings out of welded together strut, something that looks like a window frame when we're done that all the conduits have to fit through just to verify they will fit the footprint.

In your case we might build a couple of strut frames with an inside dimension of 27.5" x 35.5" used at the top and bottom of the stubs to contain them. That half inch is a little fudge factor to make sure they fit in the opening.

After they CDF all the conduits in and they're solid, we cut all the strut out that would end up showing in the concrete.

Good luck.
Attached Thumbnails
Undergrounds 5000 Amp service-160.jpg  

Undergrounds 5000 Amp service-166.jpg  

Undergrounds 5000 Amp service-164.jpg  


Last edited by Cow; 04-30-2017 at 09:28 PM.
Cow is online now   Reply With Quote
The Following User Says Thank You to Cow For This Useful Post:
telsa (04-30-2017)
Old 05-01-2017, 04:49 AM   #8
86 45 20
 
Southeast Power's Avatar
 
Join Date: Jan 2009
Location: Florida
Posts: 17,744
Rewards Points: 8,164
Default

I would suggest they either use a CT at each transformer, or CT the buss inside of the transformer.

If not, and if you are pulling 500s, why dont you look into using 3" conduit or 3-1/3" for 600s.
If you are pulling 750s, Ill be in my tent.

Something else I have done is set a slab that will fit around your conduits and terminate them at that level.
then set the slab for the CT can on top of that and only pass the conductors through the CT slab.

Last edited by Southeast Power; 05-01-2017 at 04:52 AM.
Southeast Power is online now   Reply With Quote
Old 05-01-2017, 06:58 AM   #9
Junior Member
 
Join Date: May 2015
Location: East Brunswick New Jersey
Posts: 23
Rewards Points: 6
Default

Thanks for the pics and tips!

Also, we are pulling 750 AL. Pretty annoying, but what can I say. And yeah I have never heard of a pad mounted CT before either, but hey, to each poco his own....
ElectricArmy is offline   Reply With Quote
Old 05-01-2017, 11:58 AM   #10
Senior Member
 
FaultCurrent's Avatar
 
Join Date: May 2014
Location: California
Posts: 474
Rewards Points: 887
Default

Make a plywood pattern for the stubs and use a few pieces of rebar to secure since you don't have room for the strut.
__________________
At it since 1971 and still going....kind of.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Grandpa was old, and he was slow. But he got there.
FaultCurrent is online now   Reply With Quote
Old 05-01-2017, 12:13 PM   #11
Electrical Contractor
 
wcord's Avatar
 
Join Date: Jan 2011
Location: Winnipeg, Canada
Posts: 3,812
Rewards Points: 1,580
Default

36 seems a bit small for that size service. My 400 amp services are that size. Check your shop drawings again. I would think your CT cabinet may be 60 inches wide
__________________
Nothing is to be gained by arguing with fools.
Nothing can be gained by reasoning with ignorant people.
wcord is offline   Reply With Quote
Old 05-01-2017, 06:51 PM   #12
Senior Member
 
Join Date: May 2015
Location: Sacramento, California
Posts: 13,824
Rewards Points: 25,894
Default

Quote:
Originally Posted by wcord View Post
36 seems a bit small for that size service. My 400 amp services are that size. Check your shop drawings again. I would think your CT cabinet may be 60 inches wide
I can't even visualize it.

My Poco would insist on setting one monster oil-cooled transformer next to the curtain wall of the e-room -- with it isolated by bus-duct through concrete. ( Earthquake paranoia )

The CT section would be integrated into the MDP line-up with a massive 5000A MAIN C/B.

The primary feeding the Poco's transformer would be routed under ground, of course.

The new MAIN would feed the existing MDP ... by jumpering over (tap rules) ... or adding custom busing and cabinetry provided by a NEMA player.
telsa is online now   Reply With Quote
Old 05-01-2017, 08:12 PM   #13
Junior Member
 
Join Date: May 2015
Location: East Brunswick New Jersey
Posts: 23
Rewards Points: 6
Default

I have the cuts on the CT cabinet. It is made specifically by a company in NJ for my poco - in NJ. It is about 36"x42" x 100" tall. Quite the cabinet.

I will have to include some pics when I finish for yall to see.

I like the idea about a plywood template - that will help with evenly spacing the conduits so I can put bell ends on.
glen1971 and telsa like this.
ElectricArmy is offline   Reply With Quote
Old 05-02-2017, 04:02 AM   #14
Senior Member
 
ponyboy's Avatar
 
Join Date: Nov 2012
Location: parts unknown
Posts: 8,051
Rewards Points: 709
Default

Quote:
Originally Posted by Big John View Post
I just want to see a picture of this CT. Sounds like a single giant donut? Is it zero sequence for ground fault?

Seems really strange, never heard of anyone doing a standalone "padmount" CT like that.


It's just a line/load termination with a bus bar making the "switch". Donuts go around the bus bars and the ct meter is usually bolted to the side of the cabinet. I had pictures of some I did a few years ago but they're not that pretty even when they're all dressed up. Usually there's a vault under the pad so you get the added bonus of 24+ 600 mcm conductors trying to pull the f*cking thing back into the ground. Good times.


Sent from my iPhone using Tapatalk
Big John likes this.
__________________
Too dumb for New York, too ugly for LA
ponyboy is offline   Reply With Quote
The Following User Says Thank You to ponyboy For This Useful Post:
telsa (05-02-2017)
Old 05-02-2017, 07:03 AM   #15
Retired Account
 
Join Date: Mar 2011
Location: the Green Mountain state
Posts: 39,722
Rewards Points: 14,650
Default

They make a product for this>>>




IIRC, the spacing in art 310 is for 2KV & ^


~CS~
chicken steve is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
7-unit CLUSTER-F: one service or two? mikewillnot Residential Electrical Forum 8 10-01-2016 09:11 AM
Electric Company Service Drop Upgrade MustangRider6688 Services and Service Equipment 12 07-11-2016 05:03 PM
Changing my service AK_sparky General Electrical Discussion 30 06-22-2016 09:48 PM
Upgrading 400A service to 600A Destarah Services and Service Equipment 1 03-02-2016 04:42 PM
600 volt service metering hydro Services and Service Equipment 1 01-20-2016 01:50 PM


All times are GMT -4. The time now is 10:22 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com