Heavy Duty DC Battery
Disconnecting Switch Features
Common to SD and ED types

Lock Details

Heavy Duty Contacts
The switches all have double breaking main contacts with silver alloy contact tips which are weld resistant, hard wearing and have excellent conductivity.

Lockable Version
Lockable versions of both the "SD" and "ED" switches are available. For these versions a key is necessary for the knob to be moved from the "Off" position to the "On" position. Once in the "On" position, the key can be removed. Thereafter, the knob may be depressed to the "Off" position where it will automatically lock and remained locked until the key is used again to unlock it. The suffix "L" applies for lockable versions.

Protection
Optional barriers can be fitted into the contact housing of all versions of the "SD" and "ED" switches, except for the type ED402. These should be specified when the switches are to be used in environments where there is airborne contamination.

Magnetic Blowouts
All versions of the "SD" and "ED" switches can be fitted with magnetic blowouts, except for the type ED402. These are permanent magnets situated across the contact gaps and they greatly enhance the arc rupturing capability of the switches. The suffix "B" indicates the fitting of magnetic blowouts.

Easy Installation
Mounting is by means of two 5mm screws and details of the fixing centres are shown in the diagram.

Serviceability
Both ranges are fully serviceable with replacement contacts being readily available.
For the standard versions (without lock) operating knobs are affixed by an 8mm thread and for the lockable versions knobs are retained by a circlip.

Precautions
Note: For single pole types fitted with magnetic blowouts (SD150AB, SD250AB, ED125B and ED250B), the polarity marked on the contact housing must be observed when connecting the main terminals. Ensure that the switches are installed in a position where heavy arcs emanating from the switch cannot damage or electrically jump across to adjacent parts.

For the standard versions (without lock) ensure that the knob is fully tightened. A 4mm hole in the tubular shaft housing allows a bar to be inserted which will prevent the shaft from turning during knob tightening.

The "SD" and "ED" switches are to be used to rupture current in an emergency or as a "No Load" isolator. DO NOT USE THEM AS REGULAR "ON LOAD" SWITCHING DEVICES.

No regular maintenance is necessary but in the event of an emergency switching the switches should be inspected and checked for correct operation and if necessary change the contacts before putting back into service.