40
All dimensions (mm) are nominal
Legrand powertrack systems
technical data
n
Standards
IET Wiring Regulations
The Legrand powertrack system is suitable for installation to
BS 7671 : 2001 or BS 7671 : 2008 + A1 : 2011 Requirements for
Electrical Installations
Legrand powertrack system allows compliance with regulation 543·7,
BS 7671 : 2008 and Section 607, BS 7671 : 2001.
However, this requirement must be stated at the time of order to ensure
the correct system components are selected. See installations having
high protective conductor currents (see below for further information)
n
Earth fault loop impedance
BS 7671 : 2008 + A1 : 2011 IET Wiring Regulations require accurate
determination of the total earth loop impedance, which must be
sufficiently low to allow the protective device to operate within the
specified time, which for socket outlets is 0·4 seconds. The values
relevant to Legrand for calculating the earth fault loop impedance are
shown in the electrical test data table, see
p. 41
n
Installations having high protective conductor currents
Section 543.7, BS 7671 : 2008 + A1 : 2011(formerly Section 607, BS
7671 : 2001)
To comply with this particular requirement, care should be taken when
selecting the tap-off units
Unfused tap-off units comply without the need for additional earth
conductors
Fused tap-off units would normally have 1·5 mm
2
earth conductors. To
meet this requirement the “High Integrity 543.7” tap-off units should
be specified. The 1·5 mm
2
earth conductors in these tap-off units are
replaced with 4 mm
2
conductors
These tap-off units then comply with 543.7.1.103(ii), “a single copper
protective conductor having a cross-sectional area of not less than
4 mm
2
, complying with the requirements of regulations 543.2 and
543.3, the protective conductor being enclosed to provide additional
protection against mechanical damage, for example, within a flexible
conduit”
n
Tap-off units
Section 434.2 of the Wiring Regulations requires conductors to have a
fault current protective device (e.g. fuse) at the point where the current
carrying capacity is reduced (e.g. tap-off unit)
32 A unfused 3 m tap-off units are designed to comply with regulation
434.2.1 of the IET Wiring Regulations by virtue of the following :
• maximum length of cable is 3 m
• it is factory assembled and fully tested item with cable installed in high
quality flexible conduit
Unfused tap-off units comprise of either 16 mm or 20 mm diameter
flexible metal conduit with integral 4 mm
2
LSOH conductors
Unfused tap-off units in excess of 3 m should only be used if the
powertrack system is protected by a protective device not exceeding
32 A
13 A fused tap-off units are supplied with a BS 1362 13 A fuse fitted
within the tap-off unit
This requirement refers to the total length of the cable and not the
conduit, the conduit therefore is approximately 400 mm shorter to allow
for the cable in the tap-off unit and the equipment being connected
75
93
2 x 25 Ø
46
25 Ø
46
250
47
109
118
32
15
68
65
End view A
92
End view B
Integral fixing
bracket fixing
centres
n
Dimensions
n
Pre-wired floor boxes
If a floor service outlet box, supplied by a single tap-off unit, contains
more than 2 x 13 A socket outlets then the total loading of the service
outlet box must not exceed 32 A
Unfused 32 A tap-off units in excess of 3 m should only be used if the
powertrack system is protected by a protective device not exceeding
32 A
n
General installation notes
Designed to ensure a fast and simple installation, Legrand’s low profile
powertrack system has an overall height of just 48 mm including
tap-off unit. Available in standard, clean earth and dual circuit versions,
tap-off and track connections are key coded to each range, avoiding
unintentional connection of non-compatible system components.
Standard and clean earth ranges are not interchangeable, however
tap-off units from both of these ranges can be used in the dual circuit
range. Powertrack comes in lengths of 1·2 m, 1·8 m or 3 m with tap-off
positions provided every 300 mm
Track feeder units have one or two 25 mm Ø holes for cable entries
and the terminals are suitable for conductors up to 16 mm
2
Track lengths are supplied with integral push-fit connectors
Track lengths should always be secured using the integral floor
fixing brackets
Access to power is provided along the track length by simply lifting the
plastic dust cover and plugging tap-off units into the shuttered
socket outlets
Tap-off units can feed conventional floor service outlet boxes or
workstations directly through the floor
These can be easily wired on site, or can be ordered pre-wired,
see
p. 38-39
To provide mechanical protection, 4 mm
2
or 1·5 mm
2
insulated
conductors are contained in flexible metal conduit
Care must be taken when feeding desks directly from the powertrack
system to ensure that the tap-off length is adequate
The dual circuit powertrack system incorporates both standard and
clean earth systems within one enclosure
Tap-off units from all three ranges can be used in the dual
circuit system
