MS Electronics PCTDS3 User manual

Issue 3.0
PCTDS3
Product Guide
Pull Cord Time Delay Switch
3-wire version
today, tomorrow and in the future
mselectronics.co.uk

2PCTDS3
Product Overview
The PCTDS3 Pull Cord Time Delay Switch provides med switching for lighng, heang, air
condioning and venlaon equipment. For locaons suing pull cord control, the unit oers easy
acvaon of the connected load whilst saving energy by switching it o automacally when not
required (aer an adjustable period). At any me, the acvaon period may be extended with a
further brief pull of the cord, or cancelled by holding momentarily. The unit is available with
dierent me delay ranges (see Technical Specicaon).
The unit is simple to install and ts a standard single-gang UK paress or back box (28mm min.
depth). Ideal applicaons include small booths or rooms, workshops, entrance halls, staircases,
toilets, store cupboards, hired sports courts and rooms plus many more.
Figure 1 PCTDS3
Figure 2 Typical wiring example and dimensions (in millimetres)

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Electrical Requirements
Before aempng to install the unit, ensure that the intended load and wiring arrangement comply
with the following requirements. Figure 2 shows a typical wiring example.
•3-wire (live/neutral + volt-free switch) connecon: The unit requires a permanent live/neutral
connecon, and as such is not suitable for replacing an exisng light switch with no neutral
conductor at the switch locaon. A volt-free relay output is provided, which can be used to
switch a load on the same mains supply (by connecng across from L to LIVE IN, making LIVE
OUT a switched live), or to provide a contact closure to a separate load or control signal. There is
no minimum load requirement.
Also available: PCTDS2 (2-wire version) – Suitable for ‘inline’ connecon with the load to be
switched (no neutral required), such as to replace a standard light switch. A minimum load of
20W (per switch unit) applies; a load capacitor is required for smaller loads.
•Maximum load: The maximum load rang is 16A (4000W), however for high inrush loads (such
as most types of lighng), a lower limit applies: see Technical Specicaon.
Installaon
1. Prepare a single-gang paress or back box as necessary.
2. Rotate the Timeout thumbwheel (referring to the accompanying label) to set the period of me
for which the load should remain switched on aer the pull cord is operated.
3. Connect the wiring as shown in Figure 2 (or in any suitably appropriate form).
−Supply connecons (L, N): Use appropriate mains cable to power the unit. If the load is also
powered via this wiring, ensure the current rang is adequate. Otherwise (i.e. if the output is
independently powered), low-current cable may be used.
−Load connecons (LIVE IN, LIVE OUT): Use cable rated for the load current and voltage.
−Slave switch connecons (V+, R+, R-) if required: Low-current cable may be used but must
be rated for mains voltages. See Using Mulple Switches for wiring details and slave switch
opons.
4. Fix the unit into posion with the two screws and caps supplied.
Addional Guidelines
• The screw caps may be removed at a later date with the aid of an adhesive puy such as Blu-Tack.
Ensure the electrical supply is isolated before making any connecons or adjustments.
All electrical installaon and maintenance must be carried out by a competent person. If in doubt,
consult a qualied electrician. Any new wiring must be carried out by qualied personnel in
accordance with the current edion of the IET Wiring Regulaons (BS7671).

4PCTDS3
Operaon
The diagram below illustrates the sequence of operaon for the unit.
Key
Sequence of
Operation

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Using Mulple Switches
To allow the connected load to be controlled from more than one locaon, mulple switches may be
connected, either in parallel, or using lower cost slave switches connected to a single master switch.
Example 1: Parallel Wiring
Figure 3 illustrates a typical wiring arrangement using two PCTDS3 units; Figure 4 represents the
same conguraon as applied to a typical ceiling rose lighng circuit. This method can typically reuse
pre-exisng wiring from a 2-way switching installaon where 3-core cable has been run between the
switch locaons.
Each unit operates its own ming cycle, but the load is shared. When either unit (or both) is
acvated by its respecve pull cord, the load will switch on. Once both units have med out, the
load will switch o. Note that when pulling and holding the cord to cancel the meout, the load will
remain powered if the other unit is sll in the ‘ON’ state. For full control from any switch locaon,
see Example 2.
Figure 3 Typical wiring schemac for two units
Figure 4 Typical ceiling rose plan
The following wiring examples are intended only as recommendaons. Proper wiring pracce must
be observed with relevance to the parcular installaon.

6PCTDS3
Example 2: Master with Slave Units
The remote interface feature oers the opon of lower cost 2-way or mul-way switching by
connecng up to ve slave switches to a single PCTDS3 master unit. Unlike parallel wiring (Example
1), this method retains full control from any switch locaon, and does not increase the minimum
load requirement. The master unit controls the ming cycle and switches the load, and any of the
slave switches will funcon idencally to that on the master unit.
Each slave switch may be either a PCTDS-S slave unit (which provides an idencal pull cord) or an
ordinary normally-open mechanical switch (such as a pushbuon or retracve rocker). Referring to
the steps under Installaon, connect as follows.
•PCTDS-S and other switches: Use 2-core mains-rated cable to connect to the R+ and R-
terminals only (polarity does not maer); do not use the V+ terminal. Figure 5 illustrates a
typical wiring example using two PCTDS-S slave units; Figure 6 represents the same
conguraon as applied to a typical ceiling rose lighng circuit.
Figure 6 Typical ceiling rose plan using two PCTDS-S slave units
Figure 5
Typical wiring schematic using two PCTDS-S slave units
The slave switch connecons are referenced to the mains supply of the unit, and are therefore not
safe to touch when the unit is powered. All switches and cables must be rated for mains voltages.

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Fault Finding
Load will not switch on
a) Unit is not powered
•Ensure the unit is correctly connected to an acve mains supply.
b) Load is not connected correctly
•Ensure the load is connected appropriately. The relay output is volt-free so must be
connected suitably to a supply in order to power a load.
•Check that the load works on its own by bypassing the me delay switch.
Load switches on, but does not switch o
•Ensure the set period has elapsed since the pull cord was last operated.
Technical Specicaon
Power supply
220V - 240V AC 50Hz (live/neutral)
Output switch type
Volt-free SPST (normally open) relay
Output switch rang
16A, 250V AC (resisve)
Maximum lighng load
Incandescent: 12A (3000W)
Fluorescent: 10A (2500W)
Compact Fluorescent: 10A (2500W)
Time delay selecon
3 seconds to 30 minutes or
6 seconds to 60 minutes or
12 seconds to 120 minutes
Mounng hardware
28mm (min.) single-gang UK paress box
Operang temperature
-10°C to +40°C
Guarantee
3 Years
Weight
98g
Dimensions
86mm x 86mm x 47mm
Ensure the electrical supply is isolated before making any connecons or adjustments.

IMPORTANT INSTALLATION NOTICE
The installaon of this product should be carried out in accordance with the
latest IEE wiring regulaons and all wiring completed by a qualied electrician.
Technical Support
For further help or informaon on this and the other products in the MS
Electronics range
visit www.mselectronics.co.uk or call 0333 666 1176.
Alternavely, email [e-mail]
Addional copies of this product guide can be downloaded from our website.
Product Warranty
MS Electronics guarantees all their products against manufacturing defects for
3 years from the purchase date. If your product is found to be faulty, MS
Electronics will,
at their discreon, repair or replace the product free of charge.
Note
Any modicaon or damage to the outer casing of the product, as well as any
damage to the product due to abuse or incorrect wiring may invalidate the
guarantee.
e: [email protected]
t: 0333 666 1176/01708 448566
MS Electronics reserves the right to alter or change this specicaon without prior noce.