2018 May June Marina World

MarinaGuard upgrade better
protects against ESD
The upgraded MarinaGuard Series 2 ground fault protection panels from US company Bender protect against the danger
of electric shock drowning (ESD) and meet new regulations to safeguard people at marinas, boatyards and docking
facilities across the USA and Canada.
Updates to the US National
Electrical Code (NEC, NFPA 70) 2017
significantly changed the ground fault
protection requirements for ‘Marinas,
Boatyards and Commercial and Noncommercial
Docking Facilities’.
The detection maximum limit under
the updated NEC Article 555.3 has
been lowered from 100mA to 30mA.
NEC 555.3 now requires ground fault
protection (i.e. tripping) at the 30mA
level for all over-current devices
supplying these facilities. In Canada,
the Canadian Electrical Code (CEC,
CSA C22.1) 2018 also requires 30mA
protection as described in Rule 78-052.
Electric shock drowning occurs
principally in freshwater environments,
and the threat starts with an electrical
fault condition on the dock or onboard
a boat when a voltage source comes
into contact with the body of water.
The voltage creates an electric field
that radiates throughout the water in a
hemispherical shape – like ripples from
a pebble thrown into the water.
Electric current begins to flow through
the swimmer’s body when entering
the electric field. The human body has
a much lower resistance than fresh
water so it acts as a better conductor
of electricity and, in the presence of
an electric field, the person not the
surrounding fresh water conducts the
majority of electric current.
As little as 10mA of current can
cause a loss of muscle control, which
may result in drowning. ESD is a hidden
threat as the victim may not be exposed
to the stray voltage field when entering
the water. The victim believes that the
water is safe for swimming until he or
she enters the invisible electric field.
Meeting new requirements
Bender helped to pioneer reliable
ground fault protection for marinas with
the original MarinaGuard but halted
sales in mid-2017 to prepare a design
update to meet the new standards
mentioned above.
MarinaGuard 2 operates by
immediately tripping a circuit breaker to
de-energise the faulted circuit when a
ground fault is detected. It is available
in two variants: single-channel MG-1.2
and 12-channel MG-T.2, offering one
or 12 powered trip outputs to control
shunt-trip circuit breakers.
The product is factory configured
for 30mA protection but the value can
be decreased for enhanced protection
beyond the regulatory requirement
or increased for non-NEC 2017
applications. The trip-delay time can
be adjusted to minimise de-energised
circuits when cascaded protection is
used (selective coordination).
The electrical panel is housed in
a lockable NEMA 4X enclosure that
PRODUCTS & SERVICES
conforms to NEC 555.11. A topmounted
flashing red beacon indicates
a ground-fault trip and a front panel
push button resets MarinaGuard
after a fault has been repaired or
disconnected. The units have a green
front panel ‘ready’ light to show proper
operation and a front panel ‘test’ push
button to verify protection-system
operation.
The panels provide a continuous
read-out of leakage current (if any) on a
graphical display screen.
E: industrial.sales@bender.org
www.marinaworld.com - May/June 2018 47