Hi everyone , Im hoping to get some clarity on a topic that I have not been able to get a clear answer for. We do security related stuff such as cameras , alarms etc and a bit of electrical here and there and often get asked to install backup lights run off a 12 volt battery just for loadshedding use. Do you need to be a qualified electrician to install a low voltage system like this? And do you also need to be able to do a C.O.C?
The simple answer...no
Originally Posted by silent_rain
I have a 12 VDC lighting sytem at my house connected to a solar panel and battery. A cheap quick load shedding solution.
I made the mistake of buying mezmerize solar flood lights, what a waste of a lot of money. When they work they work well, its getitng them to work, thats the real problem. For the price you pay I would have expected a lot more.
I am going to look for a better more affordable solar light solution.
I would say yes it needs to be a registered electrical contractor and a COC issued , and have pasted an extract from SANS10142-1 that lists what is covered and what is not covered
Extra low voltage lighting is listed as part of the scope
You have to be careful with regards to wiring size when running DC long distance as the resistance in the wire could prevent overload protection from operating and end up like a heater coil.
The wiring of premises
Part 1:
Low-voltage installations
1 Scope
1.1 Application of this part of SANS 10142
This part of SANS 10142 applies to electrical installations of
a) residential premises,
b) commercial premises,
c) public premises,
d) industrial premises,
e) prefabricated buildings,
f) fixed surface installations on mining properties,
g) construction and demolition site installations,
h) agricultural and horticultural premises,
i) caravan sites and similar sites,
j) marinas, pleasure craft and house boats,
k) medical locations,
l) exhibitions, fairs and other temporary installations,
m) extra low voltage lighting installations,
n) electrical installations for street lighting and street furniture, and
o) equipment enclosures (structures that provide physical and environmental
protection for telecommunication equipment).
1.2 Aspects covered by this part of SANS 10142
This part of SANS 10142 covers
a) circuits supplied at nominal voltages up to and including 1 000 V a.c. or
1 500 V d.c. The standard frequency for a.c. is 50 Hz. The use of other
frequencies for special purposes is not excluded,
b) circuits, other than the internal wiring of apparatus, that operate at voltages
exceeding 1 000 V and are derived from an installation that has a voltage
not exceeding 1 000 V a.c.,
c) any wiring systems and cables not specifically covered by the standards
for appliances,
d) all consumer installations external to buildings,
e) fixed wiring in the power supply circuits for telecommunication equipment,
signalling equipment, control equipment and the like (excluding internal
wiring of apparatus),
f) the extension or alteration of the installation and also parts of the existing
installation affected by the existing extension or alteration,
g) fixed wiring needed to connect the various units of complex machinery that
are installed in separate locations,
h) equipment for which no standard is referenced,
i) replacement or maintenance of components, and
j) earthing arrangements.
1.3 Where this part of SANS 10142 is not applicable
This part of SANS 10142 does not apply to
a) electric traction equipment,
b) automotive electrical equipment excluding the caravan part of a roving
vehicle,
c) electrical installations on board ships,
d) electrical installations in aircrafts,
e) electrical installations for underground and open cast mining operations,
f) telecommunication, television and radio circuits (excluding the power
supply to such equipment),
g) external lightning protection of buildings and structures as it is covered by
SANS 10313, and
h) extra low voltage control circuits between different parts of machinery or
system components, forming a unit, that are separately installed and
derived from an independent source or an isolating transformer (excluding
ELV lighting circuits).
Thx . I feel its more cost effective to run 12 Volts lights with a solar panel etc and a decent sized battery. than to go the full inverter route and to mess around with dbs etc. We always make sure to use correct sized cabling and not to exceed distances and try to keep it as simple as possible.
My other question that I have that a client asked me was what is the maximum distance a inverter can be placed away from the battery. I prefer to install the batteries away from the house / office as much as possible. Lets say if I had a victron phoenix inverter using 16mm cable, what would the maximum distance be from the battery that would make it safe to operate?
GCE... Would I be correct in saying it is only if the 12 VDC light are connected to the electrical installation.
I am talking about a 12 VDC system which will not be connected to the electrical installation in any form, so no isolation transfomers or any fancy stuff is required.
We need to make sure we see the whole picture, hence the simple response.
I agree 100% with the comments about low voltage, be very careful and make sure you understand that the lower the voltage the higher the current.
I would say it stills needs to be signed off with a COC looking at OHSA and SANS 10142-1 introduction - Then there is section 7.9 which refers to lights " from sources "
If you think back to the days of low voltage downlighters on 300va transformers they introduce minimal wire size which is why they disappeared and it became standard to fit 50va transformers - The length of the wire created sufficient resistance for overload protection not to operate.They ended up sizing 50sqmm wire for a 10m run with 300va load
In todays table they max load is 80Va over 10m on 10sqmm wire ( Table 7.2 Sans 10142-1 )
Have uploaded the old table from SABS 0142-1 before the change to SANS 10142-1 for interest [/I]1_20230518_0001.pdf
SANS10142-1
Introduction
In this edition an attempt has been made to move towards the IEC codes:
extra low voltage (below 50 V) and d.c. applications (up to 1,5 kV) have been
introduced as new requirements owing to the extensive usage of, and
increased fire risk that result from, high load currents. This part of
SANS 10142 does not intend to cover the LV control circuits of machinery or
system components that are external circuits between separately installed
parts of the machinery or system components.
7.9 Extra low voltage lighting installations
7.9.1.1 The particular requirements in this subclause apply to extra low
voltage lighting installations supplied from sources with a maximum rated
voltage of 50 V a.c. or 120 V d.c.
OHSA
"electrical installation" means any machinery, in or on any premises, used for the transmission of electricity from a point of control to a point of consumption anywhere on the premises, including any article forming part of such an electrical installation irrespective of whether or not it is part of the electrical circuit, but excluding
(a)
any machinery of the supplier related to the supply of electricity on the premises;
(b)
any machinery which transmits electrical energy in communication, control circuits, television or radio circuits;
Certificate of compliance
7. (1) Subject to the provisions of subregulation (3), every user or lessor of an electrical installation, as the case may be, shall have a valid certificate of compliance for that installation in the form of Annexure 1, which shall be accompanied by a test report in the format approved by the chief inspector, in respect of every such electrical installation.
(2)
Subject to the provisions of subregulation (3), every user or lessor of an electrical installation, as the case may be, shall on request produce the certificate of compliance for that electrical installation to an inspector, a supplier or, subject to regulation 4(1), an approved inspection authority for electrical installations.1_20230518_0001.pdf
So you need a COC for an alarm system and CCTV which is operating at 12- 54VDC ?
Now that we are adding 12 VDC floodlights to the alarm system which we control using the alram app, would also require a COC ?
And they are fed from a 230 VAC transfomer, connected to the electrical installation
Not an alarm system but it specifically allows for lighting to be included due to power requirements -So you need a COC for an alarm system and CCTV which is operating at 12- 54VDC ?
Now that we are adding 12 VDC floodlights to the alarm system which we control using the alram app, would also require a COC ?
And they are fed from a 230 VAC transfomer, connected to the electrical installation
1.3 Where this part of SANS 10142 is not applicable
This part of SANS 10142 does not apply to
a) electric traction equipment,
b) automotive electrical equipment excluding the caravan part of a roving
vehicle,
c) electrical installations on board ships,
d) electrical installations in aircrafts,
e) electrical installations for underground and open cast mining operations,
f) telecommunication, television and radio circuits (excluding the power
supply to such equipment),
g) external lightning protection of buildings and structures as it is covered by
SANS 10313, and
h) extra low voltage control circuits between different parts of machinery or
system components, forming a unit, that are separately installed and
derived from an independent source or an isolating transformer (excluding
ELV lighting circuits).
Isetech (19-May-23)
thanks GCE, always backed up by the facts, that what I enjoy about this forum.
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