Readers who can’t
follow Malayalam language may please excuse me for the video clip below,
featuring an electrical inspection of a proposed biscuit factory. This
hilarious film that also exposed the pathetic industrial atmosphere prevailing
in Kerala was a big box office hit and the message is relevant even today. This
clip is from the film, ‘Mithunam’, released in 1993, featuring actor Mohanlal
in the lead role of an entrepreneur whose plans are thwarted by bureaucracy
bent on extorting bribes and other pecuniary benefits. The portion shown in the
clip narrates the inspection of the factory by an electrical engineer of the
distribution company, prior to energization. The technical points raised by the
inspector and the reply are given below. The supply is low-tension, as gathered
from an earlier scene in which the engineer asks the entrepreneur to subscribe
to an insurance policy of Rs. 1 Lakh (in 1993!) to increase the rated capacity
of the local transformer.
(Inspector enters
the factory premises)
Inspector: “Where
is the diagram of the electrical circuit?”
Entrepreneur:
(hesitates) “diagram….diagram….diagram is there, sir” (pointing to some other
place)
Inspector: “Which
are the cables used? Aren’t they armoured?”
Entrepreneur:
(silent)
Inspector: (looking
at the main isolator) “Where is the ISI mark? It is mandatory”
Entrepreneur: “Sir,
sir, best switches from Delhi are used sir..”
Inspector: (looking
at a machine) “What? The same connection for lighting and machine? Don’t you
know that it should not be done?”
Entrepreneur: (folding
his hands) “Sir…sir…”
Inspector:
(irritated) “No, I am not satisfied. All this wiring should be changed”
(The inspector then
starts moving out of the factory, at which time, the entrepreneur’s elder
brother, who had a personal vendetta against the inspector intervenes and slaps
him on the face asking to sign without raising unnecessary objections. He runs
for his life and the scene ends here)
I first saw this
movie immediately after graduation. At that time itself, I wondered whether the
objections raised by the inspector are indeed valid and legal, even though the
film portrays him as a venal official readily accepting bribes. Four points are
involved in this issue.
a)
Armoured cables shall be used in
industrial installations
b)
Electrical circuit diagram shall be
readily available in an installation
c)
Lighting and power circuits shall be
separated
d)
Switches conforming to BIS standards
shall be used
Practicing
electrical engineers know that all these points are strictly adhered to, in any
industrial installation. But many people are confused as to where these
conditions appear in statutes. So I made a little research on the standards and
other rules to find out the primary source, from where these regulations have
emerged as standard practice.
Two documents that
act as guide for electrical installations in India are,
a)
IS 732: 1989, Code of Practice for
Electrical Wiring Installations
b)
SP 30: 2011, National Electrical Code
(NEC) 2011
It may be noted
that these documents will be amended periodically and obviously, the latest
amendment shall be used wherever applicable.
Now, we will see one
by one as to where in these documents our four issues appear.
1. Use of armoured cables
Clause
E-1.1.4.5 of IS 732:1989 states that “The circuits
shall be checked whether lighting wiring in factory area is taken enclosed in
conduit and conduit properly earthed, or alternatively, armoured cable
wiring is used”
Moreover, Clause
6.3.1 of NEC 2011 specifies that “For power
distribution from a substation or main switchboard to a number of separate
buildings, use shall preferably be made of armoured cables of
mineral-insulated and metal-sheathed or PVC/XLPE insulated cables“.
2.
Electrical circuit diagram
Clause 7.4.3 of IS
732:1989 states that
Diagrams, charts or tables
shall be provided indicating in particular:
a)
the type and composition of circuits (points of utilization served,
number and size of conductors, type of wiring ); and
b)
the information necessary for the identification of the devices
performing the functions of protection, isolation and switching, and their
locations.
For simple installations the foregoing information may be given in
a schedule.
3. Separate switches for lighting and power circuits
Clause
3.1.5.2 of IS 732:1989 stipulates that “Separate
circuits shall be provided for parts of the installation which need to be
separately controlled, in such a way that these circuits are not affected by
failure of other circuits”
4. Switches with ISI mark
Clause
7.1 of IS 732:1989 states that “Compliance with
Standards - All equipment fittings and accessories, materials, etc, selected
for the wiring installation shall conform to the relevant Indian Standard”
Also,
this is mandated by NEC as well as seen by clause 2.1, “Every item of electrical equipment used in the installation shall conform
to the relevant Indian Standards, wherever available”
See? Everything the engineer demanded
in the above scene was valid and mandatory!
