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#8923 - 04/09/02 08:56 PM Medium Voltage applications 12.5 kv
The Watt Doctor Offline
Member

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
I just started the process of bidding a 12.5 KV project. We had a "walk through" today, and I have to tell you that I feel like I'm in over my head, but upper management is pushing me to bid this project, and with my limited experience with voltages above 480, I'm going to put my best toe....I mean foot.... forward, and press on.
Labor units, reference materials for this type of application, etc, etc are really waxing heavily on my mind. Any advice (other than becoming chemically dependant) would be obliged.

Most Humbly, and Lostologically Yours,
Doc
_________________________
The Watt Doctor
Altura Cogen
Channelview, TX

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#8924 - 04/10/02 09:06 AM Re: Medium Voltage applications 12.5 kv
wirewiz Offline
Member

Registered: 01/27/02
Posts: 123
Loc: WA.
Hi Doc, I have had success using the means book for a pricing guide. As long as I can price each componet from the book that has allowed me enough money (including profit) to sub it out to a high voltage specialty contractor. Wirewiz

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#8925 - 04/10/02 07:05 PM Re: Medium Voltage applications 12.5 kv
electure Offline

Member

Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA
I'd try getting some bids for that portion of the work from guys that do this on a regular basis. Then add your%.
Is the 12K all the project??
I, too have personally done only a few jobs with voltages above 480 other than ducting them.
It's almost like being an apprentice again.

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#8926 - 04/10/02 08:21 PM Re: Medium Voltage applications 12.5 kv
The Watt Doctor Offline
Member

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
wiz,
I'm familiar with Means. As a matter of fact I have a Means book at the office. I guess part of the problem is, that in situations like these, I'm not even sure of "what" questions to ask. In 600 volt and lower applications, I have the experience that tells me when there are questions that I need answered.
electure, it is like being an apprentice again. As far as the majority of the project is concerned, it is just running 4" RMC. The problems come into play...well. Here is an example: A critical part of this project requires us to cut into (2)existing 12.5 kv concrete encased feeders, install an above ground tap box, and splice into the feeders. Here's the catch. The building being fed by the feeders can't be shut down for longer than a day or so. This project is for a college. Now, the feeders are a normal, and an alternate supply for the same switchgear.
My first thoughts were to set the building on alternate, and pull the normal feeder back, cut in half of the duct bank, install the tap box, repull the normal feeders, make up the stress cones, put the building back on normal power, and repeat the process for the alternate feeder. This would require our electricians to work in an energized switchgear, and for the connections in the tap box for normal power, the alternate source would be energized as well. I don't want them working in this gear while it's energized.
I'll post more as I progress through this project.

Regards to All,
Doc
_________________________
The Watt Doctor
Altura Cogen
Channelview, TX

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#8927 - 04/19/02 07:45 PM Re: Medium Voltage applications 12.5 kv
The Watt Doctor Offline
Member

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
I thought I would post an up date for those who interested in medium voltage applications.
A basic run down of my take off:

(4) Sectionalizer Terminals 15 KV, 3 phase, RTE 450LOOK29A, with 15 KV Load Break Elbows, 4-way LBC's (LBC-4) and all fittings w/stainless steel mounting strap

(1) New MCC with more motor starters than I want to list

Refeeding (2) new chillers.

Adding an 800/3 circuit breaker to existing GE switchgear, not to mention the feeder that goes with it.

(3) Toshiba VFD's

Several Disconnects

(2) Pad-mount/dead-front, 750 KVA, 3 phase, 12,470 primary, 480/277 secondary, 65 deg C temp rise, mineral oil filled with HV Surge Arrest

11,000 feet of 4" conduit (PVC, RMC, and EMT)

12,000 feet of 4/0 awg Okonite 15 KV single conductor cable

(66) Stress Cones

etc, etc, etc

The above is a "quick" list of some of the major items.

I don't know what the final tally will be, but I'm guessing it will break the 6 digit barrier. I have a Square D rep. coming in on Monday to help me insure the equipment is correct.

Kilowattingly Yours,
Doc
_________________________
The Watt Doctor
Altura Cogen
Channelview, TX

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#8928 - 04/20/02 08:02 PM Re: Medium Voltage applications 12.5 kv
Nick Offline
Member

Registered: 08/13/01
Posts: 603
Loc: Riverside, CA
Doc,
I have been actively pursuing an education in high voltage systems for many years. I finally received EC&M's Medium Voltage Power Systems a few days ago (ordered 6 months ago). I haven't gotten far into it yet. I will be looking forward to more posts from you on this topic!

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#8929 - 04/20/02 09:37 PM Re: Medium Voltage applications 12.5 kv
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
WD, are you planning to farm out the terminations or do them in-house? Some specs call for the installer to have five years of experience. The NEMA/AEIC DC tests will quickly flush out workmanship that is not “antiseptic” or materials that are improperly sized. Also, make sure to get the exact termination materials needed for your cable. Elbows are often intended for “utility” URD-type cable, and need special attention {and adapters} for use with “industrial” tape-shielded cable. There are several varieties of cable construction—make sure you’re getting the one that the engineer/facility has spec’d. Okonite is usually of good quality but some others can have a real problem with outer semicon that is not adequately free-stripping. Verify that you are specifying the right shield-grounding assemblies. Minimum bend radius on shielded cable during installation and as-left will save premature failure. For smaller jobs, it may be more convenient to use individual cable-prep kits as opposed to bulk materials. Plan on following specs for all grounding details to the letter to save rework. If you have to furnish DC testing as part of your contract, talk to several outfits if available. They probably can advise you on any concerns you have about splicing and terminations. One other thing—some cable manufacturers can be a bit ‘snobby’ to contractors that are new to this side of the business, but MV work can be profitable compared to 600V-only work.

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#8930 - 04/23/02 01:13 PM Re: Medium Voltage applications 12.5 kv
The Watt Doctor Offline
Member

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
Nick, Bjarney,
Gentlemen, thanks for your input. I submitted a bid for this project about 3 hours ago. It was a "nail bitter" because my supplier didn't get my quoted materials in until the last minute. I will let you know some of the other details later. I normally don't get very "worked up" about submitting bids, but this one, was an acception.
I've learned a few things, and if I do another one of these MV propsals again, I'll know more about what to do.

Best MV Regards,
Doc
_________________________
The Watt Doctor
Altura Cogen
Channelview, TX

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#8931 - 05/01/02 09:00 PM Re: Medium Voltage applications 12.5 kv
The Watt Doctor Offline
Member

Registered: 12/23/01
Posts: 443
Loc: Mont Belvieu, TX
Nick, Bjarney,
There were 3 electrical (sub) bidders on this project. The mechanical contractors were the "prime" bidders.
The bid tab came back as follows:
contractor #1 $443,667.00
my company $458,300.00
contractor #3 $478,000.00
Here is the catch, and I might add a very important lesson in the bidding process, the numbers are not apples to apples.

Contractor #1 included #3 & #4 rebar for the duct bank, but they excluded the (3) Toshiba freq. drives.

We included the freq. drives, but excluded the rebar. Now, if you add the rebar back in, and deduct the frequency drives from my proposal, my number is actually lower than contractor #1. Notice:
Base bid $458,300.00
Rebar $--3,400.00
Drives ($-19,400.00)
Total $442,300.00

Contractor #3 had other inclusions, and exclusions that I'm not aware of, but less than $2,000.00 spread on this size project is not bad. I will admit that there were plenty of guesses on my part. I'm not sure if my now former company is going to get the job, or not.

Kilowattologically Yours,
Doc
_________________________
The Watt Doctor
Altura Cogen
Channelview, TX

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