SDC Security Door Controls
SDC Security Door Controls
Phone Number
Home System Library Download Documents ShipQuick Inventory Sales Office Distributors Trade Shows Contacts
  Sign In
  Product Browser
  Search by Description
   or Model Number
  System Wizard
  Systems Library
  Temporary Folder
  Project Manager
  About Security Door Controls
  What's New
  Literature Request
  Industry Related Links
   Building Code & AHJ Directory
  Newsletter & White Papers
  Trade Shows
  System Engineering
  UL Listings
  About ISO 9001
  Advertising &
  Public Relations Agency
  Photo Library
  Suggestion Box
  Employment

Flash Tutorial for Website System Wizard and Project Manager

Video Tutorials

To determine the correct wire gauge to use on “one circuit” the following information is required:

  1. The quantity, voltage and current draw of all lock(s) to be used.
   2. The distance in feet from the power supply to the furthest lock.

Add together the current draw (amps) of all locks on the same circuit. Cross reference the total amps with the distance between the power supply and the farthest lock to determine the wire gauge required.

“One circuit” implies that two wires are being run from the power supply to one or more locks in parallel. The last lock on the pair of wires should not exceed the maximum distance number shown on the chart for that gauge of wire and total current draw in Amps. If the wire gauge size or maximum distance is inadequate for your application, divide the quantity of locks on that circuit to create two or more separate circuits and use the chart to figure each new circuit independently. This will increase the total number of wires being run but it will allow for a smaller gauge of wire to be used and it will increase the maximum distance from the power supply to the furthest lock on that circuit even though the same power supply is being used. The chart shows the maximum distance allowable for a 5% voltage drop from the power supply to the furthest lock on one circuit.

All wiring must be installed in accordance with all state and local codes.

Wire Gauge Charts

Ohms Law

To Determine an Unknown Voltage: E = I x R

E = Volts
I = Current, Amps
R = Resistance, Ohms
Example: .25 Amps (I) x 96 Ohms (R) = 24 Volts (E)
To Determine an Unknown Current: I = P / E

E = Volts
I = Current, Amps
P = Power, Watts
Example: 6 Watts (P) ÷ 24 Volts (E) = .25 Amps (I)
To Determine an Unknown Current: I = E / R

E = Volts
I = Current , Amps
R = Resistance, Ohms
Example: 24 Volts (E) ÷ 96 Ohms (R) = .25 Amps (I)
To Determine an Unknown Wattage: P = E x I

E = Volts
I = Current, Amps
P = Power, Watts
Example: 24 Volts (E) x .25 Amps (I) = 6 Watts (P)
To Determine an Unknown Resistance: R = E / I

E = Volts
I = Current, Amps
R = Resistance, Ohms
Example: 24 Volts (E) ÷ .25 Amps (I) = 96 Ohms (R)

Toll Free: 1.800.413.8783 Tel: 1.805.494.0622 USA Fax: 1.805.494.8861 E-mail: service@sdcsecurity.com
3580 Willow Lane, Westlake Village, California 91361 USA - Mailing Address: P.O. Box 6219, Westlake Village, California 91359 USA

© Copyright 2009, Security Door Controls, All Rights Reserved