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The Blue wire (terminal 4) must be connected to the house coloured blue or to a house terminal marked “N”. The alarm does not need to be earthed, however for convenience a spare terminal (no. 5) is provided to hold an earth wire if present. 7. Turn on the mains power to the CO Alarm circuit. Figure 5 - Surface Wiring Figure 6 - Recessed Wiring Conduit Not Suitable Locations for Surface Wiring 17 Ei220EN (Only) 1. Slide the cover off as shown in Figure 7 to expose the mounting screw holes. 2. Cut