DETA
ELECTRICAL
KNOWLEDGE IS STRENGTH
Robert Tucker, product manager at Deta Electrical, explores the various levels of
specification within the BS EN 61386 standard. As he explains, not all conduit tube is equal.
S
teel conduit tube and fittings
have been used for over
a century as part of cable
management systems for
wiring. This durable and
adaptable solution is used in
various markets around the world.
When designing cable management
systems, various aspects need to be
considered, including the location,
whether it will be used indoors, outside,
or in a clean room, its mechanical
strength, and its ability to provide an
effective bonding path.
It is all too easy, when buying
conduit tube and fittings, just to
order galvanised conduit, but how do
specifiers, installers and buyers know
they are getting a product that will meet
their specific requirements?
Levels of specification
The current safety standard for conduit
tube is BS EN 61386, and while it’s
possible to specify tube to this standard,
it’s important to consider the various
levels of specification within the standard.
This harmonised standard lays out the
performance requirements for conduit
tube, such as its mechanical strength,
bonding effectiveness and resistance
to corrosion. Each criterion has several
classification levels. The resistance to
compression criteria, for example, has a
classification range from one: Very light
Location plays a big
part in determining
requirements for a
cable management
system.
with a compression force of 125N, up to
five: Very heavy with a compression force
of 4,000N. Clearly, there is a wide range,
with a varying factor of over thirty.
It is because of these different
classification levels that if conduit is
specified by the standard alone, you
could receive a product that will not meet
your requirements.
Independent testing
Deta TTE conduit
tube is tested and
certified by BSI to
BS EN 61386.
18 | August 2017
Cable & Cable Management
Independent testing will confirm that the
product meets the standard, while the
report will confirm which classification
levels it meets. Deta TTE conduit tube
is tested and certified by BSI to BS EN
61386, confirming that it exceeds the most
demanding classification five rating for
resistance to compression, resistance to
impact and tensile strength.
It is also tested to confirm compliance
with bending, threading, electrical
bonding and ingress protection and
achieves the highest class four resistance
to corrosion classification.
Corrosion resistance is particularly
important, since the term ‘galvanised’ is
applied to a variety of different zinc coatings
used to protect iron or steel. BS EN
61386 includes several different corrosion
classifications, the most demanding being
class four, which requires both internal
and external surfaces to pass the heavy
protection corrosion test.
To achieve this rating, Deta TTE conduit
tube is galvanised on a dedicated plant
using the optimum zinc coating to provide
an extended corrosion-free life, while also
allowing the conduit to be formed on-site
without damage to the protective coating.
The final stage of the process employs a
steam blast to ensure that the bore of the
conduit is smooth and free of debris that
could damage cable insulation.
Every length of tube is marked with the
Deta TTE brand name, the BS EN 61386
standard number and is clearly marked
with a ‘Class 4’ classification.
For further information visit:
www.detaelectrical.co.uk.