when you're installing data cables and mains cables into a system there's two things that
you need to bear in mind one is the safety of the installation and the other is the reliability of
the installed system we're going to illustrate this point using this dado trunking from the
Elite Compact range from atkore so we've already got our mains cables installed here as you can
see so what's to stop me from taking this data cable and installing it into the same section as
the mains cable here well let's turn to the regs and consider that question now bs7671 refers to
voltage bands one and two and without getting too technical data cable generally falls under band
one and band 2 is your mains cable regulation 528.1 refers to the proximity of wiring systems to
other electrical services and it starts by saying that neither a voltage band 1 nor a voltage band
2 circuit shall be contained in the same wiring system as a circuit of nominal voltage exceeding
that of low voltage and a band 1 circuit shall not be contained in the same wiring system as a band
2 circuit so that seems fairly straightforward doesn't it i can't install this cable in this
section but it's interesting though that it says it can't be contained in the same wiring system
so according to that i can't even install it in this dado trunking at all or can i well the
indents that follow outline circumstances where we can in fact install data and mains cables together
so we can install them together if according to indent one every cable or conductor is
insulated for the highest voltage present so if this data cable has insulation rated at or
above the voltage in the mains cable i could run them together now there's reasons you may
not want to do that but we'll get to those in a minute are there any other options from this
regulation well indent two refers to multi-core cables indent three we're going to circle back
to in a moment indent four suggests we can install them on the same cable tray
as long as there's a physical partition that separates the cables of different bands out
intent five always seems a little bit redundant to me because it states that you can employ a
separate conduit trunking or ducting system which would kind of suggest that the cables are not in
the same wiring system it's almost as if it could read a band 1 circuit shall not be contained in
the same wiring system as a band 2 circuit unless they are not contained in the same wiring system
maybe it suggests you can install trunking inside trunking your thoughts below on that one please
indent six again refers to multi-core cables so we'll save that for another video but if we
go back to indent three now we can see that we can install data and mains cables together if
the cables are insulated for their system voltage and installed in a separate compartment of a cable
ducting or cable trunking system so this data cable is insulated to a sufficient level for
a networking system and we can indeed install it in a separate compartment of trunking such
as we've got here we can run it through this top section and comfortably meet the requirements of
this regulation even if the insulation on the data cable is not rated to the same value as the mains
cable but we said at the start of the video that we also need to think about the reliability of the
installed system and we also said that there may be other considerations as to why we wouldn't want
to run even appropriately insulated data cables along with mains cables so how do we address that
well whenever current runs through a conductor it creates a magnetic field around itself and in
an ac circuit particularly that current is always changing value which means that the magnetic field
is always changing its strength now this magnetic field is often balanced out by the current
in the returning neutral however the changing magnetic field can cut across another conductor
and generate current inside the other conductor now for another mains cable this tiny generated
current doesn't really cause any problems but inside the data cable that relies on small
currents to transmit information even a small change in that current can corrupt the data
and reduce the reliability of that data transfer so moving the data cable into this top section of
the trunking not only removes the need to find data cable with mains rated insulation it also
gets it physically further away from magnetic fields that could corrupt the data transmission
however depending on the types of loads that this mains cable is feeding and the structure of
the installed cables this distance here may not be enough to protect the data cable from those
magnetic fields so what can we do to offer further protection well we can install this specially
designed steel strip here into the top section of the trunking and connect it to the earthing system
because steel is ferromagnetic the magnetic field gets distorted and partially contained
in the steel strip when it tries to pass through the metal which means that less of the magnetic
field comes into contact with the data cables and protects the system even further from that
electromagnetic interference or emi so there we go by installing data cables and mains cables to
a high standard we can ensure that the system will remain safe and reliable but as always at
efixx we want to hear from you have you ever had issues with unreliable data transfer caused by
electromagnetic interference from cables installed in dado trunking or perhaps some other close
proximity or do you have any other tips or tricks for reducing these issues whatever the case please
leave your comments below all that remains in this video is to say thank you very much for watching