English – MEDC PB User Manual

Page 2

02/11

English

1.0 INTRODUCTION
The pushbutton unit is available with the following features:
Lift flap
Duty label
Tag label
Earth Continuity via M5 internal/external earth stud and gland earthing plate (M4 standard internal earth point

removed)
LED (encapsulated)
Resistors/ Zener Diodes (encapsulated)
Switches two maximum
Gland entries M16 or M20 in a range of positions maximum of four M20
Terminals up to 9 x 2.5 sq. mm or up to 6 x 4.0 sq. mm (all EExe rated)
Spring Return, Latching or Turn and Push Plunger.

2.0 INSTALLATION (UNIT RATED IP66/67)
2.1 Mounting Details
The pushbutton unit should be mounted on a vertical surface using the four (4) fixing holes in the base. These

fixing holes are accessible by removing the lid (see 2.4 ‘Removing the Lid’).
The fixing holes have been designed to accept a cap head screw or bolt.
MEDC recommend the use of stainless steel fasteners.

2.2 Cable Termination
Please refer to wiring diagram supplied with unit for terminal function and number.
All cable entry holes to be fitted with suitable BASEEFA certified flameproof cable entry devices, with or without

the interposition of a suitable BASEEFA certified flameproof thread adapter. Unused entries are to be fitted with

suitable BASEEFA certified flameproof stopping plugs.
Suitable flameproof cable entry devices, thread adapters and stopping plugs certified as equipment (not a

component) under an EC type examination certificate to directive 94/9/EC may also be used in the manner

specified above.
All cable glands should be of an equivalent IP rating to that of the unit, In order to maintain the IP rating of the

enclosure, the glands should be sealed to the unit using a sealing washer or sealing compound.
If earth continuity is required through the cable sheathing, then gland backing nuts must be used.

2.3 Wiring

All customer connections must be made to the numbered side of the terminal block.
All wiring to comply with the relevant wiring diagram.
MEDC recommend that all cables and cores should be fully identified.

2.4 Removing the Lid
Unscrew the four (4) corner retained fasteners, this will release the lid from the case (hexagon key size for corner

fixes 4mm AF).
Before replacing the lid, check that the lid seal is still retained in its groove.
2.5 Testing the Unit

To test the unit, press the plunger as explained in 3.0 – Operation.

3.0 OPERATION.
The unit is operated by pressing the plunger. This will either:
1. Remain in actuator position -latching type.