6730S MK (ELECTRIC), 6730S Datasheet - Page 3

• Manufacturer Part Number: 6730S
• Description: RCD, 32A
• Manufacturer: MK (ELECTRIC)
• Series: SENTRYr

Specifications of 6730S

• No. Of Poles: 2
• Voltage Rating Vac: 230V
• Svhc: No SVHC (18-Jun-2010)
• Approval Bodies: BS EN61008, IEE
• Cross-section Area Max: 35mm2
• Current Rating: 32A
• External Depth: 76mm
• External Length / Height: 81mm
• External Width: 36mm

TECHNICAL DATA SHEET
Sentry
Residual Current Devices
(RCDs)
3:5
©2001 MK Electric Limited The Arnold Centre, Paycocke Road, Basildon, Essex SS14 3EA, United Kingdom Tel: [phone] Fax: [phone] email: [e-mail] www.mkelectric.co.uk
Normal a.c. waveform
Pulsating d.c. waveform
Half wave rectified
Pulsating d.c. waveform
Typical asymmetrical
phase control
Application (continued)
3. Pulsating d.c. Fault Currents
The use of semiconductor devices in modern
electrical and electronic equipment, such as
computers, printers, plotters, televisions,
video cassette recorders and hi-fi equipment,
is growing.
Such devices may result in the normal
sinusoidal a.c. waveform generated by the
mains electrical supply being ‘modified’. for
example, the waveform may be rectified or,
as in asymmetric phase control devices, the
waveform may be chopped. The resulting
waveforms are said to contain a pulsating
d.c. component as illustrated above.
Installation
Sentry RCDs must never be used as the sole
method of direct contact protection, but are
invaluable
protection in high risk environments where
damage may occur.
Time Delayed RCDs
When two or more Sentry RCDs are installed
in series with one another, measures must be
taken to ensure that they discriminate
properly. In event of an earth fault, only the
RCD immediately upstream from the fault
should operate.
RCDs do not discriminate on rated tripping
current alone, i.e. a 100mA rated RCD
situated upstream from a 30mA rated RCD,
will not offer inherent discrimination.
In order to ensure that discrimination is
achieved, a Sentry Time Delayed RCD should
be used. The in-built time delay period
in
providing
supplementary
i
i
i
Pulsating d.c. fault current sensitive
RCDs
Should a waveform containing a pulsating
d.c. component develop an earth fault, then
it is possible that it may not be detected by
an “a.c. only” sensitive RCD. For this reason,
the Sentry range contains RCDs designed to
be sensitive to pulsating d.c. fault currents
thus maintaining the intended degree of
protection.
ensures that the downstream RCD opens the
circuit before the upstream RCD starts to
operate.
The maximum tripping time of a Sentry Time
Delayed RCD is 450ms. Typical applications
are:
i) as main incomers on TT systems where all
sockets are already protected by a 30mA
instantaneous RCD, but where unwanted
tripping may become a problem.
ii) as the main incomer of split load consumer
unit arrangement where all circuits are
protected by a 10 or 30mA instantaneous
RCD or otherwise comply with the direct and
indirect contact protection requirements of
the Wiring Regulations.
The Sentry Time Delay RCDs are clearly identi-
fied with the internationally agreed represen-
tative symbol;
S
and the words; ‘TIME DELAY’.
t
t
t
Edition 07-01