NSS

Puhli * cations

NBSIR 78-1537

An Exploratory Study of

Dielectric Breakdown Voltages

for Residential Wiring

Jose Eduardo V. Raduan

Instituto de Pesquisas Tecnologicas

Caixa Postal 7141

Sao Paulo-Brazil

and

Robert W. Beausoliel

William J. Meese

Reference

NATL INST. OF STAND S TECH R.LC.

A111D4 3 M b 7 7 5

Building Thermal and Service Systems Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

October 1 978

QC

100

U56

73-1537

Sponsored by

Office of Policy Development and Research

U.S. Department of Housing and Urban Development

Washington, D.C. 20410

WHMHSI Boreal #e Standard* mi 1

1979 '

A» CC-- '•“

NBSIR 78-1537

• A * AN EXPLORATORY STUDY OF

DIELECTRIC BREAKDOWN VOLTAGES

FOR RESIDENTIAL WIRING

Jose Eduardo V. Raduan

Institute de Pesquisas Tecnologicas

Caixa Postal 7141

Sao Paulo-Brazil

and

Robert W. Beausoliel

William J Meese

Building Thermal and Service Systems Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

October 1978

Sponsored by

Office of Policy Development and Research

U S. Department of Housing and Urban Development

Washington, D.C. 20410

MsM&QQmKU Wlfayt (JboK L

' iA 1

, U S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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SI CONVERSION UNITS

In view of the present accepted practice in this country for building

technology, common U.S. units of measurement have been used throughout

this document. In recognition of the position of the United States

as a signatory to the General Conference on Weights and Measures, which

gave official status to the metric SI system of units in 1960, assistance is given to the reader interested in making use uf the coherent

system of SI units by giving conversion factors applicable to U.S.

units used in this document.

Length 1 inch = 0.0254 meter (m)

Time 1 hour = 60 minutes = 3,600 seconds

Frequency 1 cycle per second = 1 hertz (Hz)

l
ACKNOWLEDGEMENTS

The authors appreciate the cooperation and efforts of David L. Hillhouse of the Electrosystems Division, Applied Electrical

Measurements Section, NBS for design of special hardware used in

these tests and of Walter J. Mangan for installation of hardware

and assistance during tests.

ii
CONTENTS

Page

SI Conversion Units i

Acknowledgements ii

Abstract iv

1. Background 1

2. Purpose 1

3. Surge Voltages in Residential Power Circuits 1

4. Standard High Voltage Withstand Tests 3

5. High Voltage Breakdown of Residential Wiring and Devices ... 5

5.1 Test Procedure and Test Results for NonmetallicSheathed Cable and Armored Cable Tested in Open Air ... 5

5.2 Test Procedure and Test Results for NonmetallicSheathed Cable Tested in Water 5

5.3 Test Procedure and Test Results for Flat Conductor

Cable 11

5.4 Test Procedure and Test Results for Partial Branch

Circuits 11

6. Test Summary 21

7. Conclusions 26

8. Recommendations 26

9. References 27

iii
AN EXPLORATORY STUDY OF DIELECTRIC BREAKDOWN VOLTAGES FOR

RESIDENTIAL WIRING

J.E.V. Raduan, R.W. Beausoliel, and W.J. Meese

ABSTRACT

Residential electric circuits are subjected to surge voltages resulting

from load switching in buildings, and from external causes such as lightning. Laboratory test data are presented on high voltage breakdown

values for armored cable (type AC cable), nonmetallic-sheathed cable

(type NM), flat conductor cable, and duplex receptacles. Dielectric

withstand voltage test requirements in current standards for residential

wiring and wiring devices vary over a wide range. In some cases, the

standard test voltage values for both wiring and wiring devices are less than surge voltages recorded on wiring in residences. Also field

recorded voltage wave forms and rates of their application are different

from those used in standard withstand voltage tests.

Key words: Dielectric breakdown voltages; dielectric withstand voltage

tests; residential wiring; surge voltages.

iv
1

BACKGROUND

The Building Thermal and Service Systems Division, Center for Building

Technology of the National Bureau of Standards (NBS), has an ongoing

U. S. Department of Housing and Urban Development (HUD)-sponsored

project involving the development of performance criteria and test

methods for innovative branch circuit wiring for residences. The

Service Systems Program of the Building Thermal & Service Systems

Division participated in an NBS project to assist the Brazilian

Government with the establishment of a testing laboratory for residential wiring and wiring devices.

During the electrical investigations and research activities, it was recognized that the existing high voltage withstand tests applied to

branch circuit wiring and wiring devices have considerable differences

from the standard test voltages applied to different wiring and wiring

devices. The question arises as to what applied voltage will cause voltage breakdown in the dielectric materials of wiring and devices

and what recommendations should be made relative to the test methods.

Also, the requirements for voltage transients which wiring and devices

should withstand in actual use are not well known. Such information

is important because the high voltage breakdown of wires and devices

is not only a function of the voltage but also is dependent on the

frequency of the voltage wave. Existing standards for residential

wiring and wiring devices require the application of 60 Hz constant

voltage waves rather than surge voltage wave shapes which occur naturally in normal usage of installed wiring systems.

2.

PURPOSE

The purpose was to determine the transient voltages expected in residential wiring through a literature search, and to determine the voltages

that cause failure of wiring and devices through laboratory tests.

Also, the intent was to identify the required values for development

of performance criteria and test methods.

3.

SURGE VOLTAGES IN RESIDENTIAL POWER CIRCUITS

The literature-search portion of this effort revealed that residential

electric circuits are subjected to internally generated surge voltages

resulting from load switching within the house, and externally generated surges that are likely to be caused by lightning [1], The

referenced paper presents surge voltage magnitudes and frequencies

of occurrence in residential and industrial circuits. Table 1 shows

recorded data at twenty-one locations [1]. This work was performed

over a period of two years at more than 400 locations in 20 cities.

In those houses where frequent surges were found to occur, it was shown through deliberate switching of the devices that the operation

of an oil burner, fluorescent lamp, pump, motor, refrigerator, or

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within houses in normal operation are likely to be repeated several

times a day. Such surges can generally be associated with a specific

device or appliance which may be operating erratically or exciting

a natural frequency of the wiring system. However, such surges do

not occur in all houses.

The referenced report states that conditions such as punched electrical insulation or reduced air clearances in wall outlet boxes and

similar conditions can cause flashover with 60-Hz power following.

One house was found in which a light fixture was sparking. Flashover

at 1700 volts was observed in relationship with the start of an oil

burner in the house. The defective light fixture was apparently acting

as a voltage-limiting gap for the house.

Available statistics indicate that electrically caused fires are a real problem in this country. Not including electrical fires attributed to motors or other power-consuming appliances, the National Fire

Protection Association statistics indicate that approximately 100,000

fires annually are caused by electrical wiring and general equipment.

This is approximately 10 percent of all building fires. A more detailed breakdown pertaining to the causes of these 100,000 fires was not given [2]. It is conceivable that a portion of these fires

could have been caused by high voltage flashover with 60 Hz power

following in wiring, devices, or grounded building components;

however, this hypothesis requires validation.

4. STANDARD HIGH VOLTAGE WITHSTAND TESTS

Dielectric withstand voltages are applied between insulated conductors

or terminals or other elements of opposite polarity, often including

the grounding conductor or terminal. The dielectric material of the

cable or device is subjected to a voltage considerably in excess of

the rated voltage but less than expected breakdown voltage. The withstand test voltage is intended to indicate dielectric capability to

withstand rated voltage with superimposed momentary surge or transient

voltage level resulting from circuit switching or lightning.

Examination of some standard withstand test methods has shown that a large range of withstand voltages is used for residential wiring and

devices which may be subject to surge voltages. These voltages are shown in Table 2. A number of these voltages are less than surge

voltages recorded in dwellings as shown in Table 1.

As a general rule, the standard withstand test voltages are applied at

a uniform rate of voltage increase until the withstand voltage value

is reached. The voltage at this value, is held constant for 60 seconds

and then reduced to zero at the same rate used to increase the voltage.

Breakdown any time during the test constitutes test failure.

3
TABLE 2

SUMMARY OF WITHSTAND TEST VOLTAGES

WIRING METHOD OR DEVICE WITHSTAND TEST VOLTAGE

Nonmetallic-sheathed cable[3] 5000

Armored cable [4] 1500

Flat conductor cable [5] 2000

Thermoplastic - insulated wires[6]

types T, TW:

Conductor sizes:

14-10 AWG

8-2 2000

1-4 2500

213-500 MCM 3000

501-1000 MCM 3500

1001-2000 MCM 4000

Receptacles/plugs[7] 1250

General use AC switch[8] 1500

- VOLTS

4
5. HIGH VOLTAGE BREAKDOWN OF RESIDENTIAL WIRING AND DEVICES

Selected wiring and some devices were subjected to breakdown

voltages to determine the difference between existing withstand voltage

requirements and actual voltage breakdown levels.

Breakdown tests were carried out with the cooperation and assistance

of NBS’s High Voltage Measurements Section (now the Applied Electrical

Measurements Section). The high voltage test equipment and transformer

arrangement is shown in Figure 1. The 100 kVA, 200 kV transformer

was large enough to assure essentially sinusoidal 60 Hz output voltage

as required by the ASTM D 149 [9].

5.1 TEST PROCEDURE AND TEST RESULTS FOR NONMETALLIC-SHEATHED CABLE AND

ARMORED CABLE TESTED IN OPEN AIR

Nonme tallic-sheathed cable (NMSC) having two #12 AWG copper conductors

with equipment grounding conductor and armored cable having two #12

AWG copper conductors were tested using the test specimen configuration

shown in Figure 2.

Nonme tallic-sheathed cable (type NM) and armored cable (type AC)

were subjected to a designated rate of voltage rise until voltage

breakdown occurred. At that time, breakdown voltage was recorded.

The specimens were examined for positive indication of breakdown

such as a burned hole in the conductor insulation or sheath after

each test.

Test voltage rate applications in volts per second were respectively:

750, 1000, 2000, and 4000. These values were selected to determine

the effect of rate of voltage rise on voltage breakdown values. These

rates were applied to 12 nonme tallic-sheathed cable specimens and to

12 armored cable specimens with three specimens used at each rate.

These rates are much lower than those recorded in Table 1. However,

these lower rates show a trend of voltage breakdown level related to

rates similar to those used in ASTM dielectric strength tests of

electrical insulating materials at commercial power frequencies [ 9 ]

Results obtained from the tests are shown in Tables 3 and 4. In each

case, failure occurred near the center of the specimen and was indicated

by burned conductor insulation. Burned conductor insulation was usually

visible only when the sheath was removed.

5.2 TEST PROCEDURE AND TEST RESULTS FOR NONMETALLIC-SHEATHED CABLE

TESTED IN WATER

The NMSC test of section 5.1 using the test setup in Figure 3 was

repeated with the specimen immersed in water. This test is similar to

the dielectric withstand voltage test as it appears in the UL Standard

719, Nonmetallic-Sheathed Cables [3], except that the specimens were subjected to increasing rates of voltage rise until voltage breakdown

occurred, and specimens were immersed in tap water at room temperature

5
6

Figure

1.

High

Voltage

Test

Block

Diagram
GROUNDED

CONDUCTOR

NONMETALLICSHEATHED

CABLE OR

ARMORED CABLE

\

CONNECTED

TOGETHER

WITH CLIP

LEADS

EQUIPMENT GROUNDING

CONDUCTOR

UNGROUNDED

CONDUCTOR

28"

OF INSULATION REMOVED

HIGH VOLTAGE- 60 HZ SOURCE

Figure 2. Nonme tallic-Sheathed Cable Test in Air at Room Temperature

7
TABLE 3

NONMETALLIC-SHEATHED CABLE IN AIR -

VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF TEST SPECIMEN SPECIMEN RATE OF BREAKDOWN

NO. VOLTAGE VOLTAGE - RISE - V/s kV

1 750 29.5

2 750 29.5

3 750 30.0

4 1000 30.0

5 1000 32.5

6 1000 31.0

7 2000 33.0

8 2000 33.0

9 2000 34.0

10 4000 31.0

11 4000 35.0

12 4000 35.0

Nonmetallic-sheathed cable

(two #12 AWG solid copper

conductors with grounding

conductor) tested in open

air as shown in Figure 2.

8
TABLE 4

ARMORED CABLE IN AIR -

VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF

TEST SPECIMEN

SPECIMEN

NO.

RATE OF

VOLTAGE

RISE - V/s

BREAKDOWN

VOLTAGE - kV

Armored cable (two

// 12 AWG solid copper

conductors) tested in

13 750 27.0

open air as shown in

Figure 2. 14 750 26.0

15 750 21.5

16 1000 29.0

17 1000 29.0

18 1000 30.0

19 2000 31.5

20 2000 31.5

21 2000 32.5

22 4000 31.0

23 4000 32.5

24 4000 33.0

9
FULL OF TAP WATER

Figure 3. Nonmetallic-Sheathed Cable Test in Water at Room Temperature

10
for 48 hours instead of the 24-hour immersion required by the UL 719.

No particular water quality is required by the referenced standard.

Test results are given in Table 5. These results show very little

difference from the results in Table 3 for tests in open air. In each

case, the conductor insulation was burned, which indicated a positive

break.. This break was usually visible only when the sheath was removed.

5.3 TEST PROCEDURE AND TEST RESULTS FOR FLAT CONDUCTOR CABLE

The National Aeronautics and Space Administration (NASA) developed

flat conductor cable (FCC) for aerospace applications. As a part of

their technology spin-off program, FCC was introduced by NASA as a proposed surface-mounted wiring system for residential and commercial

general purpose branch circuits using 120 V, 20 A single-phase current.

The residential application uses FCC in a baseboard configuration.

This configuration has three solid copper conductors each 0.0125 inch

thick and 0.4 inch wide. The overall width of the cable is 2 inches.

The individual conductors are insulated with polyhetylene terephthalate

(Mylar) insulation [10,11,12].

The commercial application uses FCC in an "under-carpet" configuration in office spaces to serve convenience outlets[5]. The FCC is

applied directly to the floor by way of a double backed adhesive

tape which is slightly wider than the flat cable. An 0.008-inch

thick by 5-inch wide grounded steel sheet or top shield is placed

on top of the FCC and secured by the tape. The under-carpet FCC is

similar to that used in the baseboard except that it uses conductors

which are 0.009 inch thick and 0.6 inch wide and the overall FCC

width is about 2.5 inches. The cross-sectional areas of baseboard

and under-carpet conductors are approximately the same as //12 AWG

round conductors rated at approximately 20 amperes. FCC of the baseboard system and under-carpet system types were tested in open air

using the configurations shown in Figures 4 and 5. Rates of voltage

rise in volts per second were applied to configurations as follows:

750, 1000, 2000, and 3500. Three specimens were tested at each rate

of voltage rise. Breakdown voltage was recorded. Voltage breakdown

in all FCC specimens was indicated by a burned track in the insulation

between conductors. Voltage breakdowns for baseboard and under-carpet

specimens are shown in Tables 6, 7, and 8.

5.4 TEST PROCEDURE AND TEST RESULTS FOR PARTIAL BRANCH CIRCUITS

Side-wire (wire-binding screw) and back-wire (push-in) receptacles

were tested in the configuration shown in Figure 6. Voltage

application rates of 750 volts/second and 3500 volts/second were applied to three specimens at each voltage rate until breakdown

occurred, as shown in Tables 9 and 10. It appeared that the

dielectric material in the receptacle was damaged.

11
TABLE 5

NONMETALLIC-SHEATHED CABLE IN WATER —

VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF TEST SPECIMEN SPECIMEN

NO.

RATE OF

VOLTAGE

RISE - V/s

BREAKDOWN

VOLTAGE - kV

Nonmetal lic-sheathed cable

(two #12 AWG solid copper

25 750 28.0

conductors with grounding

conductor) tested in water

as shown in Figure 3.

26 1000 29.0

27 2000 26.0

28 3500 37.0

Nonine tallic-sheathed cable

(two #14 AWG solid copper

29 750 31.0

conductors with grounding

conductor)

30 1000 30.0

31 2000 35.5

32 3500 37.5

12
36

T

8

i

B

i

2 -BASE BOARD

FCC, 2 1/2"—

UNDER CARPET FCC

l/2

H LENGTH OF

INSULATION

REMOVED AT

AB ac

CONDUCTORS

B SC TIED TOGETHER

WITH CLIP LEADS

H IGH VOLTAGE

APPLIED BETWEEN

Ad B

Figure 4. Flat Conductor Cable Baseboard or Under-Carpet Specimens

13
Figure 5. Flat Conductor Cable Under-Carpet Specimen with Top Shield

14
TABLE 6

FLAT CONDUCTOR CABLE-BASEBOARD

VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF TEST SPECIMEN SPECIMEN RATE ov BREAKDOWN

NO. VOLTAGE VOLTAGE - RISE - V/s kV

Flat conductor cable (0.4 inch 33 750 19.0*

wide by 0.0125 inch thick

conductors) of the type used

in the baseboard system tested 34 750 20.0

in open air as shown in

Figure 4.

35 750 21.0

* No hole or material 36 1000 19.5

decomposition was

found.

37 1000 22.0

38 1000 22.0

39 2000 22.5

40 2000 23.5

41 2000 23.0

42 3500 23.0

43 3500 23.0

44 3500 23.0

15
TABLE 7 FLAT CONDUCTOR CABLE UNDER-CARPET

VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF TEST SPECIMEN SPECIMEN

NO. RATE OF VOLTAGE

RISE - V/s

BREAKDOWN VOLTAGE - kV

Flat conductor cable (0.6 inch wide by 0.009 inch thick

45 750 9.5 conductors) of the type used in the under-carpet wiring

system tested in open air as 46 750 10.5

shown in Figure 4. 47 750 9.5

48 1000 10.0

49 1000 10.5

50 1000 10.0

51 2000 15.0

52 2000 15.0

53 2000 12.5

54 3500 v* 16.0

55 3500 12.0

56 3500 12.5

16
TABLE 8 UNDER-CARPET FCC TESTS INCLUDING TOP SHIELD VOLTAGE BREAKDOWN VALUES

DESCRIPTION OF TEST SPECIMEN SPECIMEN

NO. RATE OF VOLTAGE

RISE - V/s

BREAKDOWN

VOLTAGE - kV

Flat conductor cable (0.6 Inch wide by 0.009 inch thick

r'7 750 6.5 conductors) including 5 inch wide by 0.008 inch thick steel

top shield as used in the under

58 750 5.3 carpet wiring sy stein tested in open air as shown in Figure 5. 59 750 4.6

60 1000 6.0

61 1000 5.6

62 1000 5.1

63 2000 6.0

64 2000 6.3

65 2000 8.4

66 3500 6.5

67 3500 6.4

68 3500 5.6

17
STEEL

UTILITY

BOX 4”x

2-1/8” x2-

1/8

18

Figure

6.

Partial

Branch

Circuit
6. TEST SUMMARY

1. The voltage breakdown for nonmetallic-sheathed cable (NMSC) and

armored cable (BX) test specimens greatly exceeded the standard

voltage withstand test voltage values used by industry.

Standard Voltage

Cable Breakdown Voltage Range (kV) Withstand (kV)

NMSC 26 - 37.5 5

BX 21.5 - 33 1.5

Figure 7 shows the trend of increasing breakdown voltage values

as voltage application rate increases.

2. The flat conductor cables of under-carpet type without shield

experienced voltage breakdown at voltages less than half the voltage breakdown values for nonmetallic-sheathed cable and armored

cables, and FCC baseboard failed at about the lowest armored cable

voltage level.

Breakdown Voltage Range (kV)

FCC FCC

NMSC BX Under Carpet Baseboard

26 - 37.5 21.5 - 33 9.5 - 16 19.5 - 23

The baseboard FCC failed at about twice the voltage level of the

under-carpet system FCC.

The addition of the top shield to the under-carpet FCC reduced the

voltage breakdown of this FCC by about one-half.

21
Breakdown

voltage

- kV

Iriakfewn

voltage

-kV

35

30 -

25 -

2! __I

38 -

35 -

31 -

21 _

I

Figure 7

t

NMSC AMO BX TESTED

IN OPEN AIR

a #12 BX • #12 NMSC

! l J

1000 2000 3000

Rate of voltage rise - V/s

_j

4000

NMSC TESTED IN

WATER

#14 NMSC

• #12 NMSC

_ i a 1000 2000 3000

Rate of village rise - V/s

4000

Breakdown-vo It ages for Nonmetallic Sheathed Cable (NMSC)

and Armored Cable (BX)

22
Breakdown Voltage Range (kV)

FCC Under Carpet

Without Shield

FCC Under Carpet

With Shield

9.5 - 16 4.6 - 8.4

Figure 8 illustrates voltage breakdown values and voltage application

rates for the flat conductor cables.

3. American back-wire receptacles broke at considerably lower voltage

levels than American side-wire receptacles.

Breakdown Voltage Range (kV)

Side-Wire Side Wire

Back-wire (American) (Brazilian)

5.8 - 6.5 7.7 - 8.6 4.5 - 7.7

With increasing rate of voltage application, cable breakdown voltage increased, but the breakdown voltage of receptacles tended to

decrease with increasing rate. See Figure 9.

4. All wiring and devices broke at voltages in excess of the highest

surge voltage recorded in a house [1].

Highest Voltage

Recorded in a House (kV)

2.5

Lowest

Cable

Breakdown

Voltage (kV)

4.6 (Under

carpet with

top shield)

Lowe s t Receptacle

Breakd own Voltage (kV)

4.5 (Brazilian

receptacle)

23
lri®M®¥wi

voltage

- k¥

Figure 8. Comparison of Flat Conductor Cable Breakdown Voltages

24
Figure 9. Comparison of Receptacle Breakdown Voltages

25
7. CONCLUSIONS

Standard voltage withstand test methods may not simulate the rate of

rise of voltage surges that wiring and devices may encounter during

actual performance within dwellings. Breakdown voltages for receptacles

tended to decrease with increasing voltage rate of rise; therefore,

voltage withstand test methods for receptacles may imply better performance than exists in dwellings.

8. RECOMMENDATIONS

Waveforms of the type recorded in houses should be applied to cable

specimens and devices under laboratory conditions to determine a more

realistic simulation of voltage breakdown levels. See Table 1, page

2. The results may also indicate whether new withstand test methods

and voltages are required.

The effects of high voltage breakdown of residential wiring and devices

with 60 Hz power following should be investigated. Tests should be performed under various environmental conditions to study the effects of

temperature, sea air, and aging.

26
9 REFERENCES

[1] Martzloff, Francois D. and Hahn, Gerald J. } Surge Voltages in

Residential and Industrial Power Circuits , Paper 69 TP 618-EVJR,

recommended and approved by the Surge Protective Devices Committee of the IEEE Power Group for presentation at the IEEE

Summer Power Meeting, Dallas, Texas, June 22-27, 1969. Manuscript submitted February 17, 1969, made available for printing

April 7, 1969. The authors are with the Research and Development Center, General Electric Company, Schenectady, N.Y. 12305.

[2] Fire Journal , NFPA, September 1972.

[3] UL Standard 719, Nonmetallic-Sheathed Cables (ANSI C33. 56-1974)

[4] UL Standard 4, Armored Cable , October 2, 1977.

[5] Fact-Finding Report (Interim) on Flat Conductor Cable Under

Carpet Wiring System , UL File E57792 Project 75ME6795, Technology and Economics, Inc., Cambridge, Massachusetts 02138,

November 28, 1975.

[6] UL Standard 83, Thermoplastic-Insulated Wires , December 24, 1975.

[7] UL Standard 498, Attachment Plugs and Receptacles , April 1, 1974.

[8] UL Standard 20, Snap Switches , October 15, 1974.

[9] Dielectric Breakdown Voltage and Dielectric Strength of Electrical

Insulating Materials at Commercial Power Frequencies , ASTM Designation D 149-64 (reapproved 1970) also American National Standard

C59. 48-1968, American National Standards Institute - 1974, Annual

Book of ASTM Standards Part 39, American Society for Testing and

Materials, 1916 Race St., Philadelphia, Pennsylvania 19102.

[10] Hawkins, James D. , Testing of a Flat Conductor Cable Baseboard

System for Residential and Commercial Wiring , NASA Technical

Memorandum, NASA TMX-64888, George C. Marshall Space Flight

Center, Marshall Space Flight Center, Alabama, August 1974.

[11] Hawkins, James D. and Carden, James R. , Surface-Mounted Flat

Conductor Cable for Home Miring , Electronics and Control

Laboratory, NASA Technical Memorandum, NASA TMX-64887,

George C. Marshall Space Flight Center, Alabama, August 1974.

[12] Loggins, Robert W. , and Herndon, Ralph A., Testing of Flat

Conductor Cable to Underwriters Laboratory Standards , UL 719

and UL 83, Electronics and Control Laboratory, NASA Technical

Memorandum, NASA TMX-64893, George C. Marshall Space Flight

Center, Marshall Space Flight Center, Alabama, September 1974.

27
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 78-15372. Gov’t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

AN EXPLORATORY STUDY OF DIELECTRIC BREAKDOWN VOLTAGES FOR

RESIDENTIAL WIRING

5. Publication Date October 1978

6. Performing Organization Code

7. author(S) Jose Eduardo V. Raduan, Robert W. Beausoliel, and

William J. Meese

8. Performing Organ. Report No.

9. performing organization name and address

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON. D C. 20234

10. Pm^e^t/Tasjt/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP) 13. Type of Report & Period Covered

FINAL

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) Residential electric circuits are subjected to surge voltages resulting from

load switching in buildings, and from external causes such as lightning.

Laboratory test data are presented on high voltage breakdown values for

armored cable (type AC cable) , nonmetallic-sheathed cable (type NM) , flat

conductor cable, and duplex receptacles. Dielectric withstand voltage test

requirements in current standards for residential wiring and wiring devices

vary over a wide range. In some cases, the standard test voltage values for

both wiring and wiring devices are less than surge voltages recorded on wiring in residences. Also, field-recorded voltage wave forms and rates of

their application are different from those used in standard withstand voltage

tests

.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Dielectric breakdown voltages; dielectric withstand voltage tests;

residential wiring; surge voltages. '

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