ASCO Series 7000 bypass-isolation switches are available in open, closed and delayed transition designs. All ASCO bypass-isolation switches have been fully test and comply under UL-1008 ratings.
Before Underwriters’ Laboratories, Inc. will allow a transfer switch to be listed with a short circuit rating, it requires that the switch be able to close in on the same amount of fault current that it can withstand.
Consequently, in applications where extremely high short circuit current is available, fuse protection is mandatory. When coordinated with current limiting fuses, ASCO Series 7000 transfer switches have UL listed closing and withstand ratings of 200,000 amperes, at 480 VAC.
Manual Bypass/Isolation Capability Allows Emergency ATS Bypass, Maintenance and Testing
ASCO Series 7000 bypass/ isolation switches provide all the functions of an ASCO automatic transfer switch plus the ability to bypass power from a live source to load in the event the transfer switch is disabled. It also allows the transfer switch to be isolated and de-energized for maintenance, testing, or repair.
• True drawout construction allows safe, easy removal of the transfer switch and eliminates the need to make any electrical or mechanical disconnections.
• Russelectric is the only manufacturer that offers both load-break and no-load-break bypass switch designs.
1 | Bypass
To bypass the automatic transfer switch, simply slide the external bypass operating handle left to Source 2 or right to Source 1 position, and then move the handle to the “Bypass” position. This first opens the loadbreak contacts (LBLC) and then closes the bypass contacts (BPS1 or BPS2). Once in the “Bypass” position, the switch can be safely tested without affecting the load.
2 | Isolate
Once ATS is bypassed, moving the isolate handle to the “Switch Isolated” position simultaneously disconnects both primary and control power from the ATS — without having to open the enclosure door. It also physically releases the transfer switch base, which is equipped with wheels for easy removal from the enclosure for inspection, maintenance, and repair. A superior quality drawout mechanism ensures flawless positioning of the ATS for isolation.