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| Installation
Guides - |
Extensions, Alterations or Repair to an Existing Installation |
Warning
Notice
Where
cables in new colour code are installed in an existing installation
with old colour coded cables, a yellow warning notice in both
English and Chinese (see Figure 3) should be displayed at
or close to the nearest upstream distribution board (e.g.
main switchboard, sub-main distribution board or consumer
unit) of the affected installation. The warning notice should
be durable and securely fixed in position. Letters and characters
should be legible. The characters " " and "Caution"
should not be less than 10 mm in height. Other characters
should not be less than 5 mm in height. The warning notice
should have a minimum size of 100mm (width) x 75mm (height).
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| Figure
3 – |
Warning Notice |
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Single-phase
installation
Extension,
alteration or repair to an existing single-phase installation
should be wired in the colour of brown (for phase conductor),
blue (for neutral conductor), and green-and-yellow (for protective
conductor) as specified in Table 1.
| a. |
Existing
cables adopting red for phase and black for neutral
If the existing single phase installation has adopted
red colour for phase conductor and black for neutral
conductor (i.e. correctly identified), both the new and
old colour coded cables are considered unambiguously marked.
It is therefore not necessary to provide additional marking
/ label at the interface between new and old colour coded
cables (see Figure 4).
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| Figure
4 – |
Extension, alteration and repair to an existing
single phase installation, where existing phase conductors
are identified by red colour |
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| b. |
Existing
cables adopting either yellow or blue for phase and black
for neutral
Proper durable and legible labels or coding (such as cable
ties, sleeves, ferrules etc.) should be provided on the
new cables near the cable termination interface (see Figures
5(a) to 5(d)). The above provision is to standardize the
wiring work for incorrectly identified cables and to avoid
any possibility of mistaking the old “blue”
(phase) cable as the new “blue” (neutral)
cable. |
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| Figure
5 (a) - |
Addition of new colour coded cables to an existing
MCB board where phase conductor is identified by yellow
colour |
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| Figure
5 (b) - |
Extension, alteration and repair to an existing
single phase installation where phase conductor is identified
by yellow colour |
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| Figure
5 (c) - |
Addition of new colour coded cables to an existing
MCB board where phase conductor is identified by blue
colour |
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| Figure
5 (d) - |
Extension, alteration and repair to an existing
single phase installation where phase conductor is identified
by blue colour |
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Three-phase
installation
Extension, alteration or repair to an existing 3-phase installation
should be wired in the new colour code of brown/ black/ grey/
blue/ (green-and-yellow) as specified in Table 1.
At the
wiring interface, both the new and old phase and neutral conductors
should be fitted with proper durable and legible identification
marked in L1, L2, L3 and N (Figure 6).
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| Figure 6 - |
Extensions, alterations or repairs to an existing
three-phase installation |
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For
the interface between new and old colour coded cables at a
busbar chamber for an existing three-phase installation, an
acceptable means of identification is illustrated in Figure
7
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| Figure
7 - |
Interface between new and old colour coded cables
at a busbar chamber for an existing three-phase installation |
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