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Market Variability Trends Among Copper Grounding Products
Lora AboulmounaJeff Jordan, PE
Copperweld
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Is there variability in the copper market?
If so, what does that mean for performanceversus the expected
standard?
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What is the Problem?• CDEGS published a paper by Jeffrey Jordan,
PE
SHORT CIRCUIT (ISC) PERFORMANCE CONSIDERATIONS FOR CCS
• Copperweld 19 No 9 (4/0 copper equivalent)
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Assessment Overview• 5 Manufacturers:
CME, Nehring, Southwire, Republic, Cerro and Encore
• 42 total Samples:4/0, 2/0, #4, #6 wire
• Standards Referenced:IEEE Standard 80 (substation grounding
and short-circuit rating) ASTM B-3 (Soft or Annealed Copper
Wire)ASTM B-8 (Concentric-Lay Stranded Copper)ASTM B-787 (19 Wire
Combination Unilay-Stranded)
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Testing & Measurement Overview
1. Sample – cut at approximately 2 ft lengths 2. Wire diameter –
measured by a laser micrometer 3. Resistance – measured using a
resistance bridge 4. Break load – measured by taking the sum of
the
individual strands
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Standard IEEE 80 simplified formula:
𝐴𝐴𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘 = 𝐼𝐼 ∗ 𝑘𝑘𝑓𝑓 ∗ 𝑡𝑡𝑘𝑘
Application: 4/0 Substation Grounding
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Standard ASTM B-787:12.1 The cross-sectional area of the
completed conductor shall be not less than 98 % of the area
indicated in Column 1 of Table 1.
Standard ASTM B-8-11:11.1 The area of cross section of the
completed conductor shall be not less than 98 % of the area
indicated in Column 1 of Table 1.
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Standard IEEE 80 simplified formula:
𝐴𝐴𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘 = 𝐼𝐼 ∗ 𝑘𝑘𝑓𝑓 ∗ 𝑡𝑡𝑘𝑘
Application: 2/0 Substation Grounding
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Standard ASTM B-787:12.1 The cross-sectional area of the
completed conductor shall be not less than 98 % of the area
indicated in Column 1 of Table 1.
Standard ASTM B-8-11:11.1 The area of cross section of the
completed conductor shall be not less than 98 % of the area
indicated in Column 1 of Table 1.
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Preliminary Findings• 40% of the samples tested out of spec
2 wire samples met the upper limitthe remaining 50% met the
lower limit of ASTM
• None met the ultimate short circuit rating in IEEE standard 80
table 6
4/0 had 3-8% variability range2/0 had 4-8% variability range
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Standard IEEE 80 :
𝐴𝐴𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘 = 𝐼𝐼 ∗ 𝑘𝑘𝑓𝑓 ∗ 𝑡𝑡𝑘𝑘
Application: #4 Pole Grounding
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Standard ASTM B-8:11.1 … not less than 98 % of the area
indicated in Column 1 of Table 1.
Standard ASTM B-3:5.3 …. And for diameters of 0.100 in (.254 mm)
and over the wire shall not vary from the specified diameter by
more than +/- 1%, expressed to the nearest 0.0001 in (or 0.001
mm).
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Standard IEEE 80 :
𝐴𝐴𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘𝑘 = 𝐼𝐼 ∗ 𝑘𝑘𝑓𝑓 ∗ 𝑡𝑡𝑘𝑘
Application: #6 Pole Grounding
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Standard ASTM B-8:11.1 … not less than 98 % of the area
indicated in Column 1 of Table 1.
Standard ASTM B-3:5.3 …. And for diameters of 0.100 in (.254 mm)
and over the wire shall not vary from the specified diameter by
more than +/- 1%, expressed to the nearest 0.0001 in (or 0.001
mm).
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Preliminary Findings• 10% of the samples tested out of spec
– 70% met or exceeded the upper limit
• None met the ultimate short circuit rating in IEEE Standard 80
Table 6
#4 had 3-9% variability range#6 had 10-13% variability range
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Normal Distribution Model
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4/0 Distribution Model
Copper Sampling
ASTMIEEE Table 6
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Data
0
0.1
0.2
0.3
0.4
0 2 4 6 8 10
4/0
0
0.2
0.4
0.6
0.8
1
0 2 4 6 8
2/0
0
0.5
1
1.5
2
2.5
0 5 10 15
#4
01234567
0 5 10 15
#6
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Key Take-Aways• Variability in the market exists
Variability of up to 13% from IEEE short circuit
standardApproximately 25% of samples did not meet ASTM
• Further studies necessary Larger sample sizeExperimental
replicates
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Questions?• Contact Info:
– Lora [email protected](P): 615-377-4172(M):
615-270-5990
– Jeff Jordan [email protected]
Market Variability Trends Among Copper Grounding ProductsSlide
Number 2What is the Problem?Assessment Overview�Testing &
Measurement Overview�Application: 4/0 Substation GroundingSlide
Number 7Application: 2/0 Substation GroundingSlide Number
9Preliminary FindingsSlide Number 11Slide Number 12Slide Number
13Slide Number 14Preliminary FindingsNormal Distribution Model 4/0
Distribution Model DataKey Take-AwaysQuestions?
