MEDC HD1 Range User Manual

Page 3

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1.0 INTRODUCTION

The HD1 heat detector has been designed for use in flammable atmospheres and harsh environmental

conditions. The marine grade alloy (Exd) or Glass Reinforced Polyester (Exem and Exia versions) cover

and enclosure are suitable for use offshore or onshore, where light weight combined with corrosion

resistance and strength is required.

2.0 GENERAL SAFETY MESSAGES AND WARNINGS

All instructions and safety messages in this manual must be followed to allow safe installation of the

device. The device must only be installed and maintained by correctly trained site personnel/installers.

To reduce the risk of ignition of hazardous atmospheres and shock, do not apply power to the

device until installation has been completed and the device is fully sealed and secured.

ii.

To reduce the risk of ignition of hazardous atmospheres and shock, keep device tightly closed

when the circuit is energised.

iii.

Before removing the cover for installation or maintenance, ensure that the power to the device is

isolated.

iv.

Following installation, test the device to ensure correct operation.

Following installation ensure a copy of this manual is made available to all operating personnel

vi.

When installing the device, requirements for selection, installation and operation should be

referred to e.g. IEE Wiring Regulations and the ‘National Electrical Code’ in North America.

Additional national and/or local requirements may also apply.

vii.

Cable termination should be in accordance with specification applying to the required

application. MEDC recommends that all cables and cores should be correctly identified. Please

refer to the wiring diagram in this manual (or separate diagram provided with the unit).

viii.

Ensure that only the correct listed or certified cable glands are used and that the assembly is

shrouded and correctly earthed.

ix.

Ensure that only the correct listed or certified stopping plugs are used to blank off unused gland

entry points and that the NEMA/IP rating of the unit is maintained.

MEDC recommend the use of a sealing compound such as HYLOMAR PL32 on the threads of all

glands and stopping plugs in order to maintain the IP rating of the unit.

xi.

For the Exem and Exia versions, a suitable sealing washer must be fitted to all glands and

stopping plugs fitted into the enclosure.

xii.

The internal earth terminal, where fitted, must be used for the equipment grounding and the

external terminal, if available, is for a supplementary bonding connection where local codes or

authorities permit or require such a connection.

xiii.

When installing the device, MEDC recommends the use of stainless steel fasteners. Ensure that all

nuts, bolts and fixings are secure.

3.0 INSTALLATION

General

The heat detector is mounted via 4 off 9mm (Exd version) or 4 off 7mm (Exem and Exia versions)
fixing holes in feet on the base of the unit.

The fixing holes have been designed to accept M8 (Exd version) or M6 (Exe/Exi versions) screws or bolts.

The heat detector has been designed to operate in any attitude

Removing/replacing the Cover

Exd version: Unscrew and remove the 4 off M6 screws (5mm A/F hexagon key required) and lift the

cover clear of the base. The screws are not captive and should be kept in a safe place during cable

termination

Exem/Exi versions: Unscrew the 4 off M5 screws (4mm A/F hexagon key required) and lift the cover

clear of the base. The cover screws are captive and will be retained in the cover.

Once cable termination has been completed, the cover can be replaced and secured to the enclosure.

Ensure that any cover seal is correctly seated.

On Exd versions ensure that the gap between the cover and enclosure is 0.15mm max.

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