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Discussion Starter · #1 ·
First of all, let me apologize for this ridiculous question, but im starting to second guess myself.
I have a 200 amp disconnect on a building, being fed from a remote service location about 100 ' away.
I ran two 4/0 al xhhw
one 2/0 al
and a # 6 cu

At the 200 amp disconnect, I installed two ground rods.
The inspector came out and shot me down. He said I couldn't derate the grounded conductor( neutral)
Also said I only needed one ground rod.
Do I need to try again, or should I battle ?
Im not in the mood for taking it from this guy , if im correct.
Thanks
 

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I'm not an expert by any means but I thought it was alright to derate your neutral? I'm interested to see where this goes
 

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First of all, let me apologize for this ridiculous question, but im starting to second guess myself.
I have a 200 amp disconnect on a building, being fed from a remote service location about 100 ' away.
I ran two 4/0 al xhhw
one 2/0 al
and a # 6 cu

At the 200 amp disconnect, I installed two ground rods.
The inspector came out and shot me down. He said I couldn't derate the grounded conductor( neutral)
Also said I only needed one ground rod.
Do I need to try again, or should I battle ?
Im not in the mood for taking it from this guy , if im correct.
Thanks
Ralph, I don't see anything wrong with what you did. The following if per 2011 NEC and no changes appear in 2014 either.

As far as the ground rod is concerned unless you prove one rod measures <25 ohms, two are required. Did the insp. mention any Code ref? or local amendments?

220.61 Feeder or Service Neutral Load.
(A) Basic Calculation. The feeder or service neutral load shall be the maximum unbalance of the load determined by this article. The maximum unbalanced load shall be the maximum net calculated load between the neutral conductor and any one ungrounded conductor.
Exception: For 3-wire, 2-phase or 5-wire, 2-phase systems, the maximum unbalanced load shall be the maximum net calculated load between the neutral conductor and any one ungrounded conductor multiplied by 140 percent.
(B) Permitted Reductions. A service or feeder supplying the following loads shall be permitted to have an additional demand factor of 70 percent applied to the amount in 220.61(B)(1) or portion of the amount in 220.61(B)(2) determined by the basic calculation:
(1) A feeder or service supplying household electric ranges, wall-mounted ovens, counter-mounted cooking units, and electric dryers, where the maximum unbalanced load has been determined in accordance with Table 220.55 for ranges and Table 220.54 for dryers
(2) That portion of the unbalanced load in excess of 200 amperes where the feeder or service is supplied from a 3-wire dc or single-phase ac system; or a 4-wire, 3-phase, 3-wire, 2-phase system; or a 5-wire, 2-phase system
(C) Prohibited Reductions. There shall be no reduction of the neutral or grounded conductor capacity applied to the amount in 220.61(C)(1), or portion of the amount in (C)(2), from that determined by the basic calculation: See related ROP
(1) Any portion of a 3-wire circuit consisting of 2 ungrounded conductors and the neutral conductor of a 4-wire, 3-phase, wye-connected system
(2) That portion consisting of nonlinear loads supplied from a 4-wire, wye-connected, 3-phase system
Informational Note No. 1: See Examples D1(a), D1(b), D2(b), D4(a), and D5(a) in Informative Annex D.
Informational Note No. 2: A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads may necessitate that the power system design allow for the possibility of high harmonic neutral-conductor currents.
Section 220.61 describes the basis for calculating the neutral load of feeders or services as the maximum unbalanced load that can occur between the neutral and any other ungrounded conductor. For a household electric range or clothes dryer, the maximum unbalanced load may be assumed to be 70 percent, so the neutral may be sized on that basis. Section 220.61(B) permits the reduction of the feeder neutral conductor size under specific conditions of use, and 220.61(C)(1) and (C)(2) cite a circuit arrangement and a load characteristic as applications where it is not permitted to reduce the capacity of a neutral or grounded conductor of a feeder or service.
If the system also supplies nonlinear loads such as electric-discharge lighting, including fluorescent and HID, or data-processing or similar equipment, the neutral is considered a current-carrying conductor if the load of the electric-discharge lighting, data-processing, or similar equipment on the feeder neutral consists of more than half the total load, in accordance with 310.15(B)(5)(c). Electric-discharge lighting and data-processing equipment may have harmonic currents in the neutral that may exceed the load current in the ungrounded conductors. Informational Note No. 2 cautions designers and installers to be cognizant of harmonic contribution and include provisions in the electrical system design to accommodate the harmonic load imposed on neutral conductors. In some instances, the neutral current may exceed the current in the phase conductors. See the commentary following 310.15(B)(5)(c) regarding neutral conductor ampacity.
 

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First of all, let me apologize for this ridiculous question, but im starting to second guess myself.
I have a 200 amp disconnect on a building, being fed from a remote service location about 100 ' away.
I ran two 4/0 al xhhw
one 2/0 al
and a # 6 cu

At the 200 amp disconnect, I installed two ground rods.
The inspector came out and shot me down. He said I couldn't derate the grounded conductor( neutral)
Also said I only needed one ground rod.
Do I need to try again, or should I battle ?
Im not in the mood for taking it from this guy , if im correct.
Thanks
I don't see a problem, ask for code refs.
 

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Discussion Starter · #6 ·
Thanks for the responces.
I am going to battle on the neutral.
I guess if URD didn't come with a reduced neutral, I would have to re think it, but article 220.61 is dead on. A little long for some, but I see the reduction allowable.
As far as the ground rods, it was more of " a matter of fact " comment, ( trying to prove how smart he is). His reasoning was that since grounded and grounding are separate that the grounding ( eg) coming from the main service was part of the grounding electrode, which included the two that were at the main service.
I wasn't in the mood at that point. 50 $ re inspect fee .
I think I will argue this
 

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The problem is you will have to do a load calculation. Show him art. 250.24(C)(1) for the service
 

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Sorry I think you have a feeder so show him art 215.2(A)(2)
 

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Discussion Starter · #9 ·
Yeah, I figure your right.
that's ok, I can do it, I just need to find the time tomorrow before I go in there, and not pay 50 bucks
 

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Discussion Starter · #10 ·
Actually, I wouldn't be surprised if that neutral can go even smaller.
I will work on that tomorrow
 

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"Georgia has adopted statewide minimumum standard building codes which incorporate model codes (see below) and amendments. For state information contact, the Department of Community Affairs (DCA) , (404) 679-3118. There are no local Savannah amendments to the Georiga code."

From what i read there are no Georgia amendments to the NEC.

Post these items and i will do a load calc for you.

- sq foot - any deck, porches, or unfinished basement
- furnace and ac kva
- kva rating of dryer
- kva rating of range and any wall mount oven or cooktop.
- rating of any fixed in place appliances. Ex. water heater, garbage disposal, attic fan, dishwasher, hand dryer, nut fluffer.
- a picture of a kitten so I feel relaxed as I use my giant brain.
 

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Discussion Starter · #12 ·
Thanks!
2,900 s q ft
2000 watt hot water ( being used for floor heat )
12,000 wt shower steamer
washing machine
dryer - 7,500 watts
15 kw air handler
outside condenser 10,000 watts
disp,dish, Jacuzzi, inst hot , super duper plumbed in and hard wired coffee machine - 20 amp
no flour loads
 

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System: 120/240V
Square Feet: 1500
2 Small Appliance Circuit(s)
1 Laundry Circuit(s)
Water Heater: 2000 VA (Line-Line)
Dishwasher: 1500 VA (Line-Neutral)
Disposal: 900 VA (Line-Neutral)
Microwave: 1200 VA (Line-Neutral)
shower steamer: 12000 VA (Line-Line)
jacuzzi: 1500 VA (Line-Neutral)
instant hot : 1500 VA (Line-Neutral)
insane coffe machine: 2400 VA (Line-Neutral)
Dryer: 7500 VA
All Gas Cooking Appliances
Heat (Line-Line): 15000 VA
Cool (Line-Line): 10000 VA
HVAC (Line-Neutral): 350 VA
Other Motors (Line-Line): 0 VA
Other Motors (Line-Neutral): 0 VA
Largest Motor (Line-Neutral): 1500 VA

STANDARD CALCULATION:
Demand Load: 45575 VA
Minimum Current: 190 Amps
Standard or Minimum Breaker (240.6): 200 Amps
Copper Service Conductor (T310.15(B)(6/7)): 2/0 AWG
Aluminum Service Conductor (T310.15(B)(6/7)): 4/0 AWG
Copper GEC-Service (250.66): 4 AWG
Aluminum GEC-Service (250.66): 2 AWG
Neutral Load (220.61): 20075 VA
Neutral Current: 84 Amps
Copper Neutral Conductor (T310.15(B)(6/7)): 4 AWG
Aluminum Neutral Conductor (T310.15(B)(6/7)): 2 AWG
Copper EGC-Feeder (250.122): 6 AWG
Aluminum EGC=Feeder (250.122): 4 AWG

OPTIONAL CALCULATION:
Demand Load: 32150 VA
Minimum Current: 134 Amps
Standard or Minimum Breaker (240.6): 150 Amps
Copper Service Conductor (T310.15(B)(6/7)): 1 AWG
Aluminum Service Conductor (T310.15(B)(6/7)): 2/0 AWG
Copper GEC-Service (250.66): 6 AWG
Aluminum GEC-Service (250.66): 4 AWG
Neutral Load (220.61): 20075 VA
Neutral Current: 84 Amps
Copper Neutral Conductor (T310.15(B)(6/7)): 4 AWG
Aluminum Neutral Conductor (T310.15(B)(6/7)): 2 AWG
Copper EGC-Feeder (250.122): 6 AWG
Aluminum EGC=Feeder (250.122): 4 AWG
******************
Standard Calculation Details-BETA:

General Lighting/Receptacle Load: 1500sqft X 3VA/sqft = 4500 VA
Small Appliance Circuits: 2circuts x 1500 = 3000 VA
Laundry Circuits: 1circuts x 1500 = 1500 VA
Net Lighting/Receptacle Load: +5100 VA+
(220.12/52, T220.42)

Appliance Load: +17250 VA+
(220.53: 100% < 4 Appliances, 75% >= 4 Appliances)
Appliance Neutral Load: ->9000 VA<-
(220.53/61)

Dryer Load: +7500 VA+
(220.54)
Dryer Neutral Load: ->5250 VA<-
(220.54)

Cooking Appliance Load: +0 VA+
(220.55)
Cooking Appliance Neutral Load: ->0 VA<-
(220.55)

Heating/Cooling Load: +15350 VA+
(220.60)
Heating/Cooling Neutral Load: ->350 VA<-
(220.60)

Other Line Motor Loads @ 100%: +0+ VA
220.50, 430.24, 430.25, 440.6
Other Neutral Motor Loads @ 100%: ->0<- VA
220.50, 430.24, 430.25, 440.6
Largest Motor (+25%) load: +375 VA+
(220.50, 430)

Total Load: 45575 VA / 240 = 190 Amps

Neutral Load: 20075 VA / 240 = 84 Amps
******************

Optional Calculation Details-BETA:

General Load (Lights, SABCs, Laundry, Appliances, Ranges, Dryers, Water Heaters, other Motors) Total: 39500 VA
General Load Net: + 22150 VA+
General Neutral Net: ->20075 VA<-

HVACLoad: +10000 VA+

Total Load: 32150 VA / 240 = 134 Amps
Neutral Load: 20075 VA / 240 = 84 Amps


That is a lot of appliances I assumed your stove was gas.

I plugged the numbers into Electrical Wiring Pro android app. I can not recommend that app enough.

Edit: Fixed it.
 
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