SS1 Switch Stick Testing Accessory

The VON Model SS1 switch stick testing accessory is designed to be used with a high voltage DC test set such as the VON Model C-1 to quickly and thoroughly electrically test switch sticks in the field in accordance with OSHA 1910.269 (j) Live-line tools. OSHA refers to IEEE Std. 978-1984 and states that sticks will be tested to 75,000 volts per foot without designating either AC or DC voltage. On page 4378 of the January 31st Federal Register OSHA refers to the Georgia Power Company study in the discussion of the standard. This study found that DC was the best way to test sticks. On page 13 section 5.7 in the IEEE guide the statement is made that "Either ac or dc may be used (See section 1). Section 1 states "All electrical values throughout this guide, unless otherwise stated are 50 - 60 Hz rms values. Equivalent dc values as established by the user may be substituted". By continuously monitoring the current and moving the stick so that every inch is tested, the SS1 provides a faster and much more sensitive test than the 75,0000 volt test without current limits described in the IEEE guide.

OSHA also refers to ASTM F711-1969 which contains an alternate method of AC testing that does not require a 1 minute test on each section of FRP rod and tube. In the alternate method, the electrodes are energized and the stick is feed through the electrodes while the current is monitored continuously. The maximum limit in the alternate method varies from 5 to 14 microamps AC over ambient. We recommend the same limits be used for DC current limit when using the VON Model SS1 on like new sticks .

Before testing each stick should be cleaned, waxed or wiped with a silicone rag using the manufacturers recommended cleaning material. Any stick with deep scratches and exposed fiberglass should be repaired in accordance with the manufacturers recommendations before being tested. Any stick with a section whose leakage exceeds the limit should be wiped with a silicone rag and retested. If the current exceeds the limit, the stick should be pulled from service to be repaired or destroyed.

Two sets of ground electrodes and one set of energized electrodes are provided inside a grounded metal enclosure. The center high voltage electrode is energized at 75,000 volts or 100,000 volts DC. The two ground electrodes are placed 12" on either side of the high voltage electrode. The current in each ground electrode is continuously monitored by a 4" current meter. While observing the current meters, the operator who wears conductive stainless steel mesh gloves connected to ground pushes the stick into the unit keeping it in contact with the ground electrodes and the flexible high voltage electrodes.

When the operator reaches the grounded safety barrier, he then pulls out the stick in the same manner it was put in. On a dry stick at no time should the current move or exceed 10 microamps except when close to the metal end fittings. If the current exceeds the limit, the stick should be wiped with a silicon rag and tested again. If the current exceeds the limit continuously, the stick can be left in the position where the current level is highest for several minutes. Then the stick can be removed, and a check made of stick temperature to determine the exact location of the internal flaw by the heat generated.

Interior flaws of a capacitive nature are likely to only show up while the stick is moving. Thus it is a disadvantage to move the stick slowly. If any movement in the current meter is observed while the stick is being pushed into the machine, the operator should repeat the test at a faster speed. If increasing the speed causes the leakage to increase, there is an internal capacitive problem and the stick should be rejected.

Sticks can be tested wet utilizing the same test configuration. First the stick should be wet with a spray bottle or hose. Let the water dry for five minutes. IEEE Guide. 978-1984 calls for distilled water applied in a fine spray. If the stick has just been waxed it can be inserted just like it is while dry. The maximum current should not exceed 1,000 microamps. A stick that has not been recently waxed should be placed into the test compartment so that contact is made with the high voltage and ground electrodes from above. The wet stick should normally not be moved across the electrodes since this may cause a water path that would greatly increase the leakage. After a 24" section is tested, the stick would be picked up about an inch, moved to another two foot, and set straight down on the electrodes.

The Model SS1 electrodes are housed in an aluminum box 33" wide x 36" deep x 29" tall. Four retractable legs are provided which are pined in position so that the center of the feed hole is 36" from the floor. A protective curtain of stainless steel bead chain is provided so that the stick stays grounded even when the operator does not have it touching the ground electrodes on both ends.

Two 4" taut band 10 microamp meters are provided to separately monitor the current to each ground electrode. They are fully protected against electrical damage on any range. A five position range switch is provided so the current meter full scale readings can be changed from 10 microamps to 100 microamps and 1,000 microamps. A neon light is provided below each meter to give a visual indication of current transients faster than the meter movement.

The system is also available with shielded electrodes as a Model SS1-AC for those companies who wish to test using high voltage AC.

The VON Corporation, P.O. Box 110096, 1038 Lomb Avenue SW Birmingham, AL 35211 (205)788-2437