Correct Splicing Techniques
Wire splices must be kept to a minimum. Every splice increases the conductive resistance, reducing the effective distance of the electrical power or signal. Also, every splice is a potential failure point for the system due to the danger of corrosion in the wire, improper joint connections, radio frequency interference, ground faults, and other factors. Improper splices run the risk of intermittent system problems that can be very difficult to troubleshoot. Try to plan and install the site so that the only splices in the system occur in the terminal blocks that connect to each AI device. If a splice is absolutely necessary, it must be done in an above-ground, weatherproof, electrical-rated, junction box. The proper procedure for making a wire splice is as follows:
- Inside the junction box, pull an extra foot of wire for each side of the splice. This is called a service loop and allows extra wire for future service or replacement of the splice if it is done incorrectly, becomes corroded, or is otherwise damaged.
- Trim back 1½ inches of the outside insulation jacket on the cable. Do NOT strip the insulation off the individual conductor wires themselves. Place the two wires to be spliced side by side and twist them together for about ½ inch, leaving about 1 inch of wire free to be slid into a 3M U-Type connector. 3M U-Type connectors can be purchased from PTI Security Systems.
- Verify that the wires are both seated completely at the bottom of the connector. Then, using a 3M E9-Y crimping tool, crimp down the button on the connector. The crimping tool can be purchased from PTI Security Systems. For best results, crimp each connector three times in different places around the edge of the button. Verify that the button is evenly crimped all the way around and that it does not pop back up on one side.
- Wrap electrical tape around the splice and partway up the wires to help seal and protect the connection. Place a wire tag on the wires inside the junction box, identifying what the wire is connected to at each end.
- Never splice two different colors, gauges, or types of wire. It is extremely important that wire color, gauge, type, and purpose of each wire remain consistent throughout a site.