GR-1089 Fault Testing Changes for Issue 6

GR-1089-CORE has always required the Cross Voltage Test in its Section 4. This test simulates communication wires contacting power wires. Previously, the Cross Voltage Test has been conducted at 600V, but the new Issue 6 has decreased this voltage to 425V. The 425V test uses the same current levels as were required for the 600V test, so this is a decrease in the amount of power that is required to be produced by testers designed to perform the Issue 6 Cross Voltage Test. In this article, we will address the two new tables describing the tests, discuss changes and note the tests that have not changed, and offer some general guidelines for parties who would like to modify existing Cross Voltage Testers to perform the Issue 6 Test Suite at 425V.

Some authorities have decided to adopt Issue 6, but with the Cross Voltage Testing voltage remaining at the old value of 600V. Footnote 6 of Table 4-4, while not addressing the situation specifically, offers guidance in this instance by stating that the same power noted in the table for the 425V tests must be used if the tests are conducted at 600V. It is worth noting that even if the Cross Voltage Test is conducted at 600V under Issue 6, the 600V, 60A test is not conducted as it has been dropped from Issue 6. Therefore, even if your authority requires 600V testing, there is an advantage to using Issue 6.

In another change, Issue 6 simplifies the presentation of the Cross Voltage Test, with all First-Level Tests shown in Table 4-4 and all Second-Level Tests shown in Table 4-5. Previous editions of GR-1089-CORE spread the tests over several tables. This new format is much more clear.

Editorial changes have simplified the presentation of all the tests, and the deletion of the 60A 600V test has made life easier for test equipment designers. Still, Tables 4-4 and 4-5 and their footnotes are complex and have many required tests. Following the general direction of the tests in Issue 6 compared to Issue 5, Tables 4-4 and 4-5 are equivalent to or lesser than the old standard in power and voltage. Because of this rare occurrence, it is possible to revise an existing Cross Voltage Tester to have it test to the new requirements.

Some existing Power Cross Voltage Testers have only a subset of the tests noted in Tables 4-4 and 4-5 and, depending on the tests, may not need any changes or only a simple change to the input voltage (meaning that no hardware changes are required). Testers which have all the tests included will probably need some reworking. Also, please note that there will not be a drop in the power requirement of the tester itself because the most stringent test from the point of view of the testing equipment, the 277V, 25A, 15 minute test, is still included as Surge Test No. 1.1 of the Second-Level Power Fault Tests (Table 4-5).

When looking over the requirements, the first thing that is noticeable is the absence of the 1000V 5A, 600V 2.2A and the 600V 3A test, in addition to the 600V 60A test. For new AC Cross Voltage Testers made to Issue 6, this change will allow the 425V and/or 600V and 1000V tap to be built with less current capability, saving cost.

A discussion of these tests must also begin with a discussion of Table 4-5, Note 5, which applies to all 425V tests. Note 5 states, “These tests can be performed at greater than 425Vrms (i.e. 600 Vrms), with the approval of the manufacturer of the equipment, but the current is to be as specified.” Along with this information is the knowledge that Verizon has accepted GR-1089 Issue 6, but has made an exception to the 425V levels; testing for Verizon must be done using 600V.

CHANGES REQUIRED FOR UPGRADING TESTERS TO ISSUE 6

The following information is presented for evaluation of existing Issue 5 and prior testers to determine what changes and upgrades are needed to successfully test to Issue 6. In the cases of the 425V rms tests, no changes may be required if 600V as allowed under Note 5 is the only test voltage. If capability for both voltage levels is desired, a tap arrangement can be implemented to allow either voltage to be selected as required. Depending on the construction of the existing Cross Voltage Tester, one of two methods can be used to reduce the output voltage level to 425V while preserving the specified current levels. The first method is used when rheostats are employed, usually in low power tests. The second method is used when fixed resistors are used in higher output tests.

Method 1: Modification of Rheostat Taps

Rheostats are used in low power taps, and the adjustment is used to trim the output for some tests which require the current output to be set at the circuit protection value. In these circuits, no tester rework will be needed, but any calibrations done on the rheostats will have to be performed again by conducting a short circuit test with a current meter connected. The variac or voltage supply should be set for 425V, and the rheostat should be adjusted to produce the desired current flow. In the spreadsheet below, we have noted the probable rheostat taps as “Low Power”.

Method 2: Modification of Fixed Resistor Taps

Fixed resistor taps are used for the higher power output requirements. When reducing the voltage and keeping the current constant, the changes are relatively simple as no further resistances need to be added. A typical tap will use a number of fixed resistances and, at the end of the tap, a variable resistor used to compensate for resistor tolerance. To make the changes, it is necessary to swap the variable resistor to the new end position of the new bank (Figure 1).

Figure 1: Demonstration of resistance change

GR-1089, Table 4-4, First-Level Power Fault Tests

Unchanged Taps

Table 1 shows the First-Level Power Fault Tests. There are some tests which are carried over verbatim from Issue 5; there are no changes to older AC Power Fault Testers for the tests shown.

Taps Requiring Changes

Issue 6 does have some changes for the First-Level Tests. These changes are due to the relaxation of test voltage from 600 to 425V. Depending on the requirements of your testing authority, these changes may not be needed if testing is to continue at 600V. If testing at 425V is anticipated, the changes should be evaluated, as some of the adjusted taps may require reworking (Table 2).

Table 2: Table 4-4 First-Level Power Fault Tests (click image for larger version)

GR-1089, Table 4-5, Second-Level Power Fault Tests

Unchanged Taps

Table 3 notes the unchanged Second-Level Power Fault Tests. These tests are carried over verbatim from Issue 5; there are no changes to older AC Power Fault Testers for the following tests shown in Table 3.

Taps Requiring Changes

Issue 6 has some changes for the First-Level Tests. These changes are due to the relaxation of test voltage from 600 to 425V. Depending on the requirements of your testing authority, these changes may not be needed if testing is to continue at 600V. If testing at 425V is anticipated, the changes should be evaluated, as some of the adjusted taps may require reworking (Table 4).

Conclusion

Issue 6 of GR-1089-CORE reduces the voltage level for the Cross Voltage Test as shown in the newly edited Tables 4-4 and 4-5. The previous level of 600V has been reduced to 425V and the 600V, 60A test has been dropped. In the tables shown above, we have given general guidelines for the hardware changes needed to refit a tester made for GR-1089-CORE Issue 5 to test to the new Issue 6 requirements.

Despite the relaxation of the Cross Voltage Test in Issue 6, Verizon has advised that starting in 2012, testing will be done to Issue 6 but using the previous 600V test levels. Until it is clear that the 425V levels will be used, testers should delay making any changes to existing Issue 5 test equipment, while new purchasers should explore procuring a tester that can provide 425 and 600V levels. Any changes to Issue 5 testers should be made in a fashion that still allows use of the 600V taps.

Jeffrey D. Lind is president of Compliance West, USA and has contributed his 33 years of extensive electrical engineering expertise to help further the advancement and expansion of the Compliance West, USA brand. Jeff’s comprehensive understanding of the industry, ranging from sales and marketing to product development, has helped establish Compliance West as a driving force within the medical and industrial testing industries.Jeff launched his career in the electrical product safety industry working at Underwriters Laboratories (UL) from 1976-1982 doing project engineering and follow up services management. He then lent his skills to Atari™ as a product safety engineer for a year. Shortly after moving to San Diego in 1983 to work with Sega Gremlin™, Jeff decided to branch out on his own and launched Compliance West. As President, Jeff approves and implements all business management decisions, runs all financials and budgeting and oversees the engineering, customer service, and marketing departments. Compliance West USA prides itself on listening to its customers’ needs and finding solutions to the challenges they face. These one-on-one customer relationships have enabled the company to enhance its products and capabilities on a consistent basis. Currently the company is introducing RS-232/USB connectivity across its line of surge and hipot testers, and offering custom test solutions to labs and companies worldwide through its domestic and international distribution network. Compliance West, USA has become the most trusted name in hipot and surge testing equipment internationally for industries across the board, ranging from medical device manufacturing and telecom to computer technology and the solar energy market. Jeff received his Bachelors of Science in electronic engineering from Cal Poly San Luis Obispo in 1976. A former downhill bicycle racer, Jeff enjoys biking and camping with his 8 year old twin sons.

José Cabanillas has been with Compliance West, USA since 2005. He started out building testers for the company and was promoted to Engineering Manager in 2007. José is responsible for hardware design on new products and maintenance and improvement of existing designs.Previously, José worked in Instituto Arangure as a Mathematics and Physics teacher in Tijuana B.C., Mexico from 2002 through 2004. He then worked as a Product Engineer at Sharp Electronics (SEMEX), in Rosarito, Mexico from 2004 through 2005. José received his Degree in Electronic Engineering from Instituto Tecnologico de Sonora, located in Cd. Obregon, Sonora, Mexico in 2002.