ECN Forum Forums Code Related Discussion NEC & other Code issues Size feeder??

Thanks Greg and Tesla. That's what I figured it had to be on the clamps. I always like to cover all my bases when going into a job. Most of the time I overdo it, but I'd rather over do than under do. As far as doing something out of my field, Electricity is my field. I do understand there is a lot I have not done, and I'm very careful to try and not get in over my head. Work is scarce and I cannot afford to turn down work if there is a possibility I can do it.
To Tesla: As far as cable is concerned for a drop, I HAVE NOT seen a 3 phase 200 amp copper feeder cable with a ground and neutral. Do they make such a thing? If so, looks like it would be so heavy it would not be feasible to hang from the ceiling. Be like fighting a giant Anaconda snake
Thanks for all the input.. Steve

Southwire Armorlite MC cable comes in 3/0-4 with ground (black/red/blue/white and a bare ground)
I bet it ain't cheap and I am sure it will be a special order in most places but it is available.

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet262

It says it weighs 2.8 pounds a foot. (2709 per m)

Wow!! This age of technology never ceases to amaze me. I learned a long time ago that I don't know everything:)

Greg, what page of Southwire did you get this information. I would like to know the cost of (4) 3/0's with a ground in this cable. Be interesting to compare the cost with installation in pipe.. Thanks, Steve

http://www.southwire.com/products/ArmorliteTypeMC.htm

This is on their web site.

I am not sure about prices and minimum orders. I would start with my local dealer.

One drawback I heard from an EC was the support requirements for the MC feeder size was not thought about when he switched from pipe to MC feeder. He was not a happy guy!

I don't work the industrial side of the street, but my general impression from NECA shows is that cable tray holding MC up through feeder sizes has taken off.

Greenlee has a whole series of specialty tools entirely directed at pulling in MC -- over pre-existing MC -- in industrially sited cable trays.

For the situation at hand, you might be well off buying even second hand MC from Salinger or its competition. You only need a trivial amount.

BTW, the big move has been to aluminum -- to include Bus Duct.

IIRC Westinghouse invented Bus Duct and put it on the market circa 1938. Eventually that division made its way to Cutler Hammer.

As popular as it is for industry, Bus Duct took off in the high rise sector. Tugging in big conductors vertically is brutal. Bus Duct is why going vertical has been so much more economic since WWII.

Hey Sparkync,

I compiled a few Panel Schedules, per the spec's of the Project described in this Thread, and posted them as PDFs at the Technical Reference Area.

These items may be found under the Topic:
Example Panel Schedules - Per Thread at NEC Area.
*Note: Click the underlined text above to jump to that page.
Page will open in a new Tab or Window.

Per the Schedules:

Post Message #1 of 2 contains Schedules 1M and 2M.

"Panel: 1M" (Example #1) has the 208V 1 Phase 2 Wire Motor Loads' VA entries figured at:

a. 20 Amps x 208V = 4,160VA
4,160VA / 2 = 2,080VA per Phase.

and

b. 30 Amps x 208V = 6,240VA
6,240VA / 2 = 3,120VA per Phase.

-----------------------------------------------------------

"Panel: 2M" (Example #2) has the 208V 1 Phase 2 Wire Motor Loads' VA entries figured at:

a. 20 Amps x 120V = 2,400VA
2,400VA per Phase.

and

b. 30 Amps x 120V = 3,600VA
3,600VA per Phase.

--------------------------------------------------------
STATS FOR PANEL "1M":

Max. Load: 163.67 Amps on Phase "A", and 40.00 Amps on the Common Grounded Neutral Conductor.

% Volt Loss on the 25 Foot 3/0 THHN CU. Feeder is 0.32% L-L and 0.11% L-N.

SCA at the Panel = 10,435A - figuring:
10KA at the Distribution Panelboard (Feed Point),
1,830A Motor Contribution.

------ ------- ------ ------ ------ -------

STATS FOR PANEL "2M":

Max. Load: 185.00 Amps on Phase "A", and 40.00 Amps on the Common Grounded Neutral Conductor.

% Volt Loss on the 25 Foot 3/0 THHN CU. Feeder is 0.36% L-L and 0.11% L-N.

SCA at the Panel = 10,435A - figuring:
10KA at the Distribution Panelboard (Feed Point),
1,830A Motor Contribution.

-----------------------------------------------------

Schedules 1M and 2M have only the 1 Pole Loads designating the L-N Amperes / VA.
This is evedent in the lower tally fields, where the totals are shown per Phase and Neutral.

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Per the Schedules:

Post Message #2 of 2 contains Schedules 3M and 4M.

"Panel: 3M" (Example #3) has the 208V 1 Phase 2 Wire Motor Loads' VA entries figured at:

a. 20 Amps x 208V = 4,160VA
4,160VA / 2 = 2,080VA per Phase.

and

b. 30 Amps x 208V = 6,240VA
6,240VA / 2 = 3,120VA per Phase.

-----------------------------------------------------------

"Panel: 4M" (Example #4) has the 208V 1 Phase 2 Wire Motor Loads' VA entries figured at:

a. 20 Amps x 120V = 2,400VA
2,400VA per Phase.

and

b. 30 Amps x 120V = 3,600VA
3,600VA per Phase.

--------------------------------------------------------
STATS FOR PANEL "3M":

Max. Load: 163.67 Amps on Phase "A", and 163.67 Amps on the Common Grounded Neutral Conductor.

% Volt Loss on the 25 Foot 3/0 THHN CU. Feeder is 0.32% L-L and 0.45% L-N.

SCA at the Panel = 10,435A - figuring:
10KA at the Distribution Panelboard (Feed Point),
1,830A Motor Contribution.

------ ------- ------ ------ ------ -------

STATS FOR PANEL "4M":

Max. Load: 185.00 Amps on Phase "A", and 185.00 Amps on the Common Grounded Neutral Conductor.

% Volt Loss on the 25 Foot 3/0 THHN CU. Feeder is 0.36% L-L and 0.51% L-N.

SCA at the Panel = 10,435A - figuring:
10KA at the Distribution Panelboard (Feed Point),
1,830A Motor Contribution.

-----------------------------------------------------

Schedules 3M and 4M have ALL Loads designating the L-N Amperes / VA.
This is evedent in the lower tally fields, where the totals are shown per Phase and Neutral.

Would like everyone to review these items and post comments.

TIA!

--Scott (EE)

*** Follow-Up ***

Did the Values in these (4) Schedules make sense, or should I post more details?

--Scott (EE)

Speaking of feeder sizes, was this question asked before?

You can use #2 AL wire for a 100 amp service in a rsei install. If you use #2 AL for a feeder, you have drop the rating down to 9 amp. Right?

What about a generator? The wire from the generator to the transfer switch is #2 Al. So the generator OCP should be 100 amp? 90 amp?