Boating New Zealand - July 2018

86 Boating New Zealand

Marine-grade wiring can be expensive, and boat owners on

a budget may question why cheaper automotive cable can’t be

used. he answer is corrosion. Even the highest-grade untinned

copper wire will corrode over time, even within the insulation.

Another common problem on older boats, says Douglas, is

the use of underrated cable – a 10-amp bilge pump running

over two-amp cable. his can lead to failure at a critical moment

when that pump is most needed, resulting a minor issue

becoming a major one.

Using non-marine-grade cabling is false economy, and if the

boat’s going into survey, approved cable types have to be used or

it won’t pass inspection. his may be harder to install and more

expensive, but it is safer in the long run and will last for decades.

When designing the new cable layout, there are a couple of

basics to consider. A large inboard diesel engine may draw 300

amps or more when starting. his demands large-diameter (and

Although minor changes to the 12V (or 24V) system can sometimes

be tackled by a competent DIYer, mains power alterations must

be left to the experts. New legislation being introduced this year

mandates that all mains voltage installations require a compliance

certificate, which can only be issued by a certified marine

electrician. This applies not just to circuits connected to shore

power but also onboard generator or inverter-driven circuits.

Douglas says lots of larger vessels coming into New Zealand

have 110-volt mains circuits. These require large step-down

transformers to connect to shore power. Added to this, many older

vessels have thermoplastic sheathed (TPS) mains wiring installed,

which again is now illegal. “When we see this product in a boat,”

says Douglas, “we only have two legal options: refuse to do any

further work, or rewire and replace all that cable.”

Note that this regulation has applied to New Zealand houses for

some years, as many buyers of older properties have discovered to

their dismay.

MAINS POWER

RIGHT CZone’s digital switching solutions

have an added advantage – much easier

control and monitoring.

OPPOSITE This is what your new

switchboard should look like.

OPPOSITE BOTTOM Consider fitting

underwater LEDs to give your boat a lift.

...digital switches

can simplify the

wiring, and certainly

add some ‘smarts’

to how items are

controlled.