A Introduction 2
B Product Range 3
C Safety Instructions 5
D Installation 6
E Operating Instructions 18
Switch Modules, Enclosures,
Neon Indicator Modules
56420 GRY, 56421 GRY, 56422 GRY, 56836, 56881, 56882,
56883, 56889, 56891, 56892, 56893, 56896, 56910, 56915.
F Testing 19
G Fault Diagnosis 20
H Service and Maintenance 22
I Disposal Instructions 23
J Guarantee 23
Please leave this leaflet with the 1 consumer for future reference
C. SAFETY INSTRUCTIONS
1. It is essential that, prior to installation or maintenance, the
user/installer disconnects the electrical supply before
2. This product should be installed by a competent person
(e.g. a qualified electrician) in accordance with the instructions
supplied with the product and in accordance with the
appropriate clauses of the current edition of the IEE wiring
regulations (BS 7671).
3. It is essential that all connections are made as instructed, that
cables are not stressed and that terminals are fully tightened .
4. All switches, except push switches, do not have to be derated
when used with fluorescent or inductive loads. All switches
conform to BS3676 Pt. 1 1989
5. If metal conduit enters the back box in more than one position,
earth continuity must be maintained.
6. These products conform to their relevant British Standards,
Switches BS 3676 Pt.1 and Neons BS 5733, are manufactured in
accordance with BS EN ISO 9002 and comply with the LV
3. Drill out the drain hole if required (see Fig. 1). The complete
profile should be filed out taking care not to damage the small
Congratulations on the purchase of another quality MK product.
The Masterseal range consists of surface mounted switches, 13A
socket outlets, a photo-electric switch, an RCD protected socket
outlet and enclosures to accommodate various modules.
The various modules comprise 10A and 20A switches, 240V and 24V
Switches and enclosures are provided with a fluorescent locator
neon that remains lit regardless of the switch position.
Made from a tough thermoplastic material, the Masterseal range of
products are robust and suitable for use indoors and outdoors,
wherever corrosion resistance, dirt and moisture proofing is required.
All products accept MK push-in conduit and cable entries, which
compliment the range (see Service Items).
Switch products and enclosures meet a rating of IP56.
If you are in any doubt regarding the application or installation of this
product, please contact MK Technical Sales Service Department on
01268 563720 or your local MK Representative.
1. The enclosure should only be mounted in the vertical plane on a
flat surface from which all grease, dirt and loose material has
2. Position back box ensuring that one of the drain hole features is
located at the bottom left hand corner.
3. Prior to mounting the enclosure, the blank fitted at the required
cable entry, should be removed and replaced with the desired
conduit entry or coupler (see Service Items).
4. If conduit enters from the top or side of the enclosure, the drain hole
must be drilled out using a 5mm diameter drill bit, to allow any
condensation formed in the conduit system to drain out of the unit.
Opening of the drain hole will reduce the IP rating, therefore ensure that
jetted water is not directed at the unit if the drain hole is used.
5. Drain holes should not be drilled out if the product is to be
located in an excessively dusty environment (eg. a sawmill). Only
bottom conduit entry should be used.
6. If conduit enters from the bottom of the enclosure, and it is
necessary for the IP rating of the product to be retained, a
condensate hole of at least 5mm diameter must be provided at
the lowest point of the conduit run.
4. Using the dimensions in Fig. 2, mark the positions of the screw
fixing holes ensuring that conduit or cable is aligned with the
appropriate centre line on the diagram.
5. Drill the screw fixing holes to accept an appropriate wall fixing.
B. PRODUCT RANGE
10A SWITCH MODULES
List No. Description Max.
56881 1 Way S.P. 10AX
56882 2 Way S.P. 10AX
56883 1 Way D.P. 10AX
20A SWITCH MODULES
List No. Description Max.
56891 1 Way S.P. 20AX
56892 2 Way S.P. 20AX
56893 Intermediate 20AX
56896 1 Way D.P. 20AX
7. Metal conduit can be earthed using the earth lead adaptor
(see Service Items).
8. If wiring directly into the unit without using conduit ensure that
a cable specified for outdoor use is used with the cable entry.
9. PVC cable entry should only enter from the bottom of the enclosure
using the cable entry.
10. If used, conduit must be sealed to the conduit entry using a nonsetting
conduit adhesive such as Egaweld No. 2. It is not
necessary to apply adhesive to the enclosure/conduit joint.
11. A locator is provided on all switch products and is intended to
remain lit at all times regardless of the switch position, if wired
as shown in Fig. 5, page 16. Replacement locators are available
(see Product Range list for details).
12. Use No. 8 wood screws for fixing box to wall.
13. WARNING: Do not allow any form of paint or wood
preservative to come into contact with any part of these
products, as they may damage the plastics used.
These products can safely be mounted on surfaces coated
with paint/preservative when they are dry.
WARNING: ALWAYS ENSURE THAT THE MAINS SUPPLY IS
DISCONNECTED BEFORE COMMENCING WORK.
Procedure for Installing Modules
1. The modules are intended to be installed once only. If removed
from the front plate and re-installed the effectiveness of the snap
fit will be impaired and may reduce the performance of the
2. If the membrane seal is not in the correct position the IP rating
of the product may be affected.
Once you have decided on the type of enclosure and modules you
wish to use, proceed as follows:
1. Remove the front plate from the enclosure.
2. Clip the required modules onto the front plate from the back
ensuring that the “TOP” marking on the module is adjacent to
the “TOP” marking on front plate (see Fig. 3). When fitting a
single module, this should be fitted on the left hand side (as
viewed from the back).
3. Ensure that the module clips are securely latched to the lugs on
the rear of the front plate (see Fig. 3).
List No. Description Dimensions
H x W x D (mm)
56420 1 Gang Switch 95 x 95 x 38
56421 1 Gang Switch and Neon 95 x 95 x 38
56422 2 Gang Switch 95 x 95 x 38
NEON INDICATOR MODULES
56889 240V RED
56890 Neon Locator 31 x 7 (Dia)
56460 Entry Blank 26.9 (Dia) x 5.25
56461 PVC Cable Entry 26.9 (Dia) x 28
56462 20mm Plain Conduit Entry 26.9 (Dia) x 28
56463 20mm Threaded Conduit Entry 26.9 (Dia) x 28
56464 Box Coupler 26.9 (Dia) x 16.5
9933 M20 Earth Lead Adaptor
1. Remove front plate from the enclosure.
2. Push out the blank fitted to the required cable entry point and
replace with the desired conduit entry or coupler (see Fig. 1).
Note: The entries will be easier to insert if warmed in the hand
prior to manipulating into the box. Ensure that the groove on the
entry is fully located onto the box wall.
4. If a neon indicator module is being used, ensure that the neon is
located on the correct side of the front plate (see Fig. 4) as
indicated by the membrane seal. Neon modules are installed as
described on pages 12 and 13.
PROCEDURE FOR REMOVING THE MODULES
If a module is found to be faulty or unserviceable and requires
replacement, proceed as follows:
1. Using a flat bladed screwdriver carefully lever the uppermost
module clips upwards over the front plate lugs and remove
module (see Fig. 7).
2. If the module clips break during this procedure ensure that all
loose parts are removed from the product.
REPLACEMENT OF NEON LOCATOR
The neon locator should be replaced whenever it is found to be
Replacement locators are available (refer to Product Range
To replace a neon locator proceed as follows:
(a) Switch off and disconnect the mains supply to the product.
(b) Remove the front plate and disconnect the locator wires.
(c) Using a flat bladed screwdriver remove and discard the
faulty locator referring to Fig. 9.
(d) Fit new locator, pushing into place, and, referring to Fig. 5,
wire in position.
(e) Refit front plate and reconnect and switch on the mains
supply to the product.
5. Locate the conduit or cable in the required entry and screw the
back box to the wall.
6. Fit the required modules to the front plate (see page 12).
7. Before fitting front plate ensure that the holes in the box seal are
aligned with the fixing screw holes and the slot around the seal
is aligned with the ribs in the enclosure.
8. Refer to the wiring diagram (Fig. 5) and wire in position. Ensure
that wires are of sufficient length to allow easy access to rear of
front plate, but short enough to fit comfortably inside enclosure
when front plate is secured.
Note: If the enclosure seal is not correctly positioned the IP rating of
the product may be affected.
E. OPERATING INSTRUCTIONS
1. Press lower edge of rocker until engaged in ON position
(see Fig. 8).
2. On those products fitted with a neon indicator ensure that the
indicator lights when the switch is ON.
3. On units fitted with Press Switches ensure that the rocker
returns to the OFF position when released.
H. SERVICE AND MAINTENANCE
1. The exterior of the products should only be cleaned using a
solution of mild detergent (eg. washing-up liquid) and warm water.
2. Polycarbonate is a highly durable material which is ideal for use
in most environments. However you should seek advice from
MK Technical Sales Service Department before installing in
environments where chemicals, synthetic oils or harsh cleaners
are likely to be used.
S.P. 1 WAY
56881 / 56891
S.P. 2 WAY
56882 / 56892
D.P. 1 WAY
56883 / 56896
1 GANG AND
Note: Completed installation should be tested in accordance with
the latest edition of the IEE wiring regulations (BS 7671).
I. DISPOSAL INSTRUCTIONS
Product and packaging should be disposed of via civic amenity
facilities at the end of its useful life.
The company undertakes to replace or repair at its discretion
products should they become defective within 20 years in the case of
electromechanical Wiring Device products and 10 years in the case
of mains related electronic Wiring Device products and all Circuit
Protection and Cable Management products solely as a result of
faulty materials and or workmanship. Understandably if the product
has not been installed or maintained in accordance with the
company’s instructions, has not been used appropriately or if any
attempt has been made to rectify, dismantle or alter the product in
any way the guarantee will be invalidated.
This Guarantee states the company’s entire liability. It does not
extend to cover consequential loss or damage or installation costs
arising from the defective product. This Guarantee does not restrict
or infringe the normal statutory or other rights of the consumer.
9. Fit the front plate to the enclosure. Do not overtighten the front
plate fixing screws (see Fig. 6).
Front Plate Fixing Screws
G. FAULT DIAGNOSIS
1. If the service (e.g. lights) connected to the product fails to
operate, check the service is functioning, the wiring is correct
and the main fuse is intact. Then either contact your local
electrician or proceed as follows:
(a) Switch off and disconnect the mains supply to the switch.
(b) Remove front plate and check that wiring is correct in
accordance with the relevant wiring diagram and all
terminals are sufficiently tightened.
(c) Replace front plate, reconnect and switch on mains and
check operation of service (e.g. lights).
(d) If service (e.g. lights) still fails to operate, switch off and
disconnect mains supply and contact MK Electric Technical
Sales Service Department or your local MK Representative.
2. If, on those products fitted with neon indicators, the indicator
fails to light, the complete neon module should be replaced.
Contact MK Electric Technical Sales Service Department or your
local MK Representative.
MK Electric wishes to make it clear that it owns all the original
designs of the products which it manufactures (whether or not listed
in this leaflet) and that it will take all necessary legal action in any
part of the world against any party found to be manufacturing,
distributing, selling or otherwise dealing with any article which
infringes the company’s copyrights or patents in its products, or any
other right of the company therein.
Registered Design No. Patent Pending
Design Right M.K. Electric Ltd.
It’s simply safer to say MK
MK Electric Limited
The Arnold Centre, Paycocke Road, Basildon, Essex SS14 3EA
Telephone 01268 563000 Facsimile 01268 563563 (UK Sales)
Facsimile 01268 563360 (International)
Web site: www.mkelectric.co.uk
All marks in this document identified with a ® or symbol
adjacent to the mark are Trade Marks of MK Electric Limited 40433PL Ed.6