By Gerhard Hope
Prefabricated or modular wiring systems have the power to deliver improved margins and time-savings on electrical installations with zero-harm, zero-waste products that are faster and safer to install – so why are more electrical contractors not switching allegiance from hard-wiring?
Electrical installation procedures have changed little in decades,
with hard-wiring having been the necessary and often preferred option for contractors,
despite industry predictions that modular would be the norm by now. In relation
to 16A and 20A lighting systems, pre-wired plug-and-play systems have been in the
market for some time. However, the innovation by Marshall-Tufflex of a small 32A
plug-and-play connector has done away with the need for hard wiring to floor boxes
or trunking accessory boxes, and opened up a whole new range of possibilities for
Marshall-Tufflex’s MT32 prefabricated wiring system allows electrical
contractors and engineers to provide a complete electrical wiring installation by
extending and interlinking pre-wired products all the way from the main power source
under the floor to the desk and to lighting and perimeter systems via its simple
plug-and-play connection system – in short, MT32 can deliver a complete electrical
wiring installation. It is still unfamiliar territory for many, and some electrical
engineers perceive it is not always suitable for their projects.
“However, we have a rapidly growing bank of projects that prove
just how successful, effective and straight-forward a pre-fabricated wiring system
can be, with installations ranging from police headquarters to hotels, prestige
office developments/refurbishments, schools/accommodation blocks and mixed use commercial
projects,” comments Marshall-Tufflex international technical sales manager Svetislav
“Our MT32 prefabricated wiring solution has also been used within
multi-occupancy residential developments. Electrical designers and contractors who
have dipped their toes and road-tested the system quickly realise it offers real
commercial and end-user benefits that, quite simply, cannot be ignored for future
projects,” says Bulajic.
He cites the advantages as being “immense and futuristic”. Speed
of installation is one of the main benefits. A contractor can e-mail AutoCAD drawings
to the supplying manufacturer, and it will design the modular system and supply
it all ready to be plugged in.
A complete installation is achieved from the distribution board
to the furthest point of a circuit by simply clicking the connectors together, or
by using a project-specific Home Run [the electrical cable that carries power from
the main circuitbreaker panel to the first electrical box, plug, or switch in the
circuit]. “The thinking behind prefabricated systems is simple – to reduce the amount
of electrical work carried out on-site,” says Bulajic.
Rather than collecting together the individual components for
a particular task and assigning an electrician to assemble them, the electrical
contractor purchases the finished unit, in theory recouping the extra cost of the
component in time saved on-site. Immediately this raises concerns that electrical
contractors will face a drop in income if they employ a modular approach. Not so,
“Broadly speaking, jobs are priced as contracts, and that approach
does not change. What does change is time spent on-site, which can be reduced by
50% or more (or months off a year-long project). Initial outlay for a modular system
is slightly higher than that for hard-wiring, but this extra cost is quickly recouped
by significantly lower labour charges, delivering monetary savings of up to 50%.”
Time- and cost-savings of this level are possible because modular
systems are delivered to site ready for connection. Design and planning work is
done in advance. “For Marshall-Tufflex clients, this means supplying us with project
drawings, enabling us to evaluate the electrical requirements of the scheme, measure
the lengths of cables required, number of Home Runs needed, etc.
“This information is used by our clients to price the contract
and, once given the go-ahead, we fabricate the components, which are then sent to
site fully factory tested and boxed up ready for installation,” explains Bulajic.
Modular solutions work on a radial circuit rather than a ring
main. The radial approach is well accepted around the world. There are proven advantages
to installing radial circuits. For example, these circuits use far less copper cable,
so there is less time spent on installation and therefore lower costs.
And that is in addition to the savings being made through use
of a modular wiring system. Faults are less likely, and easier to identify. Radial
circuits can offer a quicker, more cost-effective and safer way to work with less
drain on copper resources and speedier inspection and testing. “For contractors
and electrical systems designers wishing to try a modular approach, we can offer
design and technical support, particularly for the first project.
“We also advise including your modular manufacturer in project-design
discussions at the earliest possible stage in order to get maximum benefits from
using a pre-fabricated system. That said, it is possible to switch a hard-wired
specification to modular,” says Bulajic.
Pre-wiring and factory testing provides major time-savings during
second-fix, as well as offering safe and problem-free connection, while keyed connectors
guarantee cable sizes are correctly matched and ensure correct polarity. Project-specific
pre-wired Home Runs reduce the requirement for cable containment such as steel conduit
and overhead metal trunking systems. This simplifies installation at any given location,
but particularly so where containment is situated above ceiling and in partition
walls. Modular systems reduce time spent working at height pulling cables through.
Less time spent working on elevated platforms, podiums and step ladders delivers
obvious health and safety benefits.
“Hard-wiring is a wasteful procedure in new installations, as
cable runs are usually installed with an over-run of cable that converts into financial
loss. This waste is commonplace in the commercial environment, where many thousands
of metres of wiring can be stripped out during an office refurbishment. Prefabricated
systems lend themselves brilliantly to re-use and can be virtually zero waste,”
“In the case of MT32, the system can be disconnected using a
small screwdriver, and the cabling runs re-used where appropriate. This reusability
makes prefabricated wiring a brilliant proposition for permanent and temporary electrical
installations such as office blocks, hospitals, schools and commercial premises,
as well as modular buildings like housing, apartments, student accommodations, temporary
installations and exhibitions stands.”
All modular wiring systems require installation by qualified
electricians to ensure they are fitted in accordance with the IEE Wiring Regulations
17th Edition: BS7671:2008. Marshall-Tufflex works closely with all relevant mechanical
and electrical consultants qualified to produce electrical designs and calculations
in order to integrate modular wring plans into design drawings.