wheelock DB4 INSTALLATION INSTRUCTIONS

Technical Manual for the

Speaker – DB4

Please note that every care has been taken to ensure the accuracy of our
technical manual. We do not, however, accept responsibility for damage,
loss or expense resulting from any error or omission. We reserve the right
to make alterations in line with technical advances and industry standards.

© MEDC 2001 06/01

1. INTRODUCTION

These speakers have been designed for use in harsh environmental conditions.

2. INSTALLATION
General

When installing and operating explosion-protected electrical equipment, require­ments for selection, installation and operation should be referred to eg. IEC
60079-14 worldwide and the ’National Electrical Code’ in North America.
Additional national and/or local requirements may apply.

Ensure that all nuts, bolts and fixings are secure.
Ensure that only the correct UL listed stopping plugs are used to blank off unused

gland entry points and that the NEMA/IP rating of the unit is maintained.
The DB4 is mounted via 2 x Ø 0.354” (9 mm) fixing holes in the ‘u’ shaped

stirrup/mounting bracket. The fixing holes have been designed to accept an M6
screw or bolt. MEDC recommend the use of stainless steel screws.

The elevation of the unit can be adjusted by loosening the 2 x M6 screws which
fasten the stirrup to the horn. The unit can then be adjusted by rotating to the
required position and then tightening the M6 screws. The DB4 should be posi­tioned such that debris, dust or water cannot settle in the re-entrant horn.

Cable Termination

CAUTION: Before removing the cover assembly, ensure that the power to the
unit is isolated.

Unscrew the 6 off screws holding the cover to the unit. Twist the cover gently
clockwise and anti-clockwise, whilst pulling it away from the unit. Remove to gain
access to the interior of the base.

Cable termination should be in accordance with specifications applying to the
application. MEDC recommend that all cables and cores should be fully identi­fied.

Ensure that only correct UL Listed cable glands are used and that the assembly is
shrouded and correctly earthed.

All cable glands should be of an equivalent NEMA/IP rating to that of the speaker
and integrated with the unit such that this rating is maintained.

Once termination is complete, carefully push the cover back onto the unit, avoid­ing damage to the mating surfaces. Tighten the 6 off cover screws evenly, to

ensure maintenance of the required gap between the cover and enclosure.

06/01 © MEDC 2001

3. OPERATION

The speaker is available in 3 standard wattage ratings. Different sound levels can
be obtained by selecting the transformer tappings in the unit.

GENERAL ARRANGEMENT

ALL DIMENSIONS IN INCHES AND MILLIMETERS

4. MAINTENANCE

719/32"

193mm

POSITION 2 IS USED IF ONLY
1 x 1/2" NPT ENTRY IS REQUIRED

8W VERSION

23/32"

13/16"
30mm

13/16"
30mm

53mm

Ø 45/8"

Ø 117mm

2 x 1/2" NPT ENTRIES MAX

15W & 25W VERSIONS

1011/16"
271mm

FIXING HOLE Ø 1/2" /13mm

71/4"

184mm

Ø 53/8"

Ø 137mm

FIXING HOLES Ø 11/32" / 9mm (2 POS.)

Ø 611/16"

Ø 170mm

During the working life of the unit, little or no maintenance is required. However,
if abnormal or unusual environmental conditions occur due to plant damage or
accident etc., then visual inspection is recommended.

If a fault should occur, it is recommended that the unit be returned to MEDC for
repair. All parts are replaceable.

If you have acquired a significant quantity of units, it is recommended that spares
are also made available. Please discuss your requirements with the Technical
Sales Engineers at MEDC.

© MEDC 2001 06/01

5. CERTIFICATION/APPROVALS

Please refer to marking on the unit for specific approval details.

● UL listed for use in Class 1, Zone 1, AExd IIC T4.

USA (USL) and Class 1, Division 2, Groups A, B, C & D.
Canada (CNL)

● UL Standards UL2279 & UL464.

6. CERTIFIED TEMPERATURE

–55°C to +55°C
–67°F to +131°F

MEDC Ltd, Colliery Road, Pinxton, Nottingham NG16 6JF, UK.
Tel: [phone] Fax: [phone]
Sales Enq. Fax: [phone] Sales Orders Fax: [phone] MEDC Stock No.
E-mail: [e-mail] Web: www.medc.com TM105-ISSA