Q. What is the application of an In-Line Disconnect? A. In-Line Disconnects are used for line sectionalizing during service restoration and "By-Passes"
at recloser installations.
Q. Other than conventional type In-Line Disconnects, what other types of switches are used? A. S&C, Hubbell and Bridges provide pole mount and cross arm mounted switches. The
difference is that they are not “In Line” switches. However some of them perform similar functions.
Q. Why would a customer use a tension In-Line Disconnect versus a pole or
cross arm mounted? A. Several reasons:
a. The pole is already congested with equipment, leaving no room for disconnects
b. There is no easy access to the pole for truck
c. It could be a temporary situation such as construction or relocation of a line
Q. Who sells the tool? A. S&C along with AB Chance
Questions regarding the In-Line Disconnect Q. What are the critical pieces of information we need to determine the correct BURNDY®
switch required for the application? A. Line conductor size, Current (BURNDY® switch is 900 amps), Voltage level
Q. What are the key components of the switch that change because of voltage? A. The switch blade and the insulator string, increased blade length and number
of insulators
Q. Is the BURNDY® product RUS Listed? A. Not at this time. We plan to have the product listed when we complete the testing
on the balance of the switches.
Q. Is there a specific direction for orientation of the In-Line Switch? A. Yes, the linemen know how to position the switch (based on current flow), so this answer is
for your background information. The switch should be oriented so that when the blade is open,
it is in direction of the current or what is typically the downstream load side of the conductor.
Explanation: The switch blade has two ends. The hinge end and the jaw end.
The jaw end is where they use the Loadbreak tool. This should always
be the hot end or current direction. When the blade is in the down position the blade is not
hot. The jaw end is then live. This is because you stopped the current load.
Q. Is there an advantage in having the electrical and mechanical loads of the switch
channeled through one contact point on the line? A. Some customers want to use two connections to the standard switch, one for mechanical
and one for electrical. Very common. This way they can disconnect the electrical portion of
the switch for maintenance. There could be a disadvantage of using this method.
If you lose the electrical connection of the switch the current then has the opportunity of
going to the mechanical connection and could cause issues. This has not happened on a
regular basis, however could be a potential issue. We have one connection that is designed to
handle both the electrical portion as well and mechanical application.
Questions regarding the Insulators Q. What is a Polymer insulator? A. A polymer insulator is manufactured from a composite type of material (silicon/EDPM), other
than glass
Q. What types of materials are used? A. Glass, Silicon, EDPM
Q. Why is Silicon used more than EDPM or Glass? A. Over a period of time dirt and other containments attach themselves to the insulators.
(This is why you see insulators getting cleaned or washed.) Because of the nature of Silicon
this effect is greatly minimized. This process is called Hydrophobicity. You can compare this
to waxing your car in which water beads up.
