ALARM SYSTEMS PRETORIA GAUTENG SOUTH AFRICA

Alarms and Security Systems Pretoria Midrand Johannesburg Gauteng

 
Alarms and Security Since 1992 Business Hours (Std ZA Time GMT +2)
Monday - Thursday 08:30 - 16:30
Fridays 08:00 - 14:00

Closed on weekends and public holidays
223 Tulip Road
Mnandi, Centurion

GPS: S25° 53' 01.0" E28° 04' 26.9"

Click Here For Map

Security and CCTV Systems
Tel: 012 668 1184
Cell: 082 456 4700

 
 
Surge Protection
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SURGE PROTECTION

Why Surge protection is required in South Africa

 Security in South Africa is the number one priority. When you purchase or rent a building, the first thing you do is secure it. Part of securing a business today is having a failsafe security system that runs on clean UPS power or at least, protecting the building against surges would be the minimum precaution.

Did you know that the total lightning strikes per annum for South Africa average ±20 000 000 strikes! The probability that your house or factory will be directly hit is still small but it only need to be as close as two kilometer from you to damage your electronic equipment.

The failure of a technical system like your factory or house alarm, or any other equipment like your TV & CCTV renders a very unpleasant operation. These require faultless operation from the equipment both under “normal’ conditions and in the case of thunderstorms. Loss report of insurance companies show clearly that there is a 45% risk of lightning / surge damage per year to your equipment
The lightning protection zones concept enables Alarman to plan, perform and implement protection measures tailored for your specific requirements
All relevant equipment and installations are protected reliably and furthermore with economically accepted effort
 
Sources of interference
Surges arise due to;
 
1.       Thunderstorms
 
2.       Electrical supply variations (surges) from the supplier (e.g... municipality, private institution or Eskom)
 
We will concentrate on thunderstorms as supply variation from item 2 above can be accommodated into that. Surges arise due to direct / close lightning strokes or distant lightning strokes.
Direct or close strokes are strokes into the lightning protection system of a structure (e.g.. strike the pole outside the house or strike the building itself)
Due to the amplitude and energy loads, the arising impulse currents and impulse voltages represent a special risk for the system we must protect typically ≥ 33kAmp.
 
1.       Direct lightning strokes - LPZ 0
Direct and close direct lightning stroke protection equipment is bound by internationally standardized testing specifications. The characteristic parameters of flowing impulse currents can be described with the impulse-current wave form 10/350 µs (This means: Rising a current from 0 to 100kA max within 10µs then sloping down to 50kAmp at 350µs and degrading to ≈18kA at 1000µs) and are defined as test currents for components and devises for the protection against average direct lightning strikes (≥33kAmp).
 
Some powerful strikes cannot easily be diverted, like the "Positive Up" strike. It is very powerful and literally destroy everything in the way.
 
2.       Distant lightning strokes – LPZ1&2
Distant lightning strokes and surges arise in the electrical structure (mostly wires) and connected systems and equipment due to the induction effect of the electro-magnetic lightning field.
 
The power of these induced surges and the resulting impulse currents is considerably lower than the power of a direct lightning impulse current and is therefore only described with the impulse current wave 8/20 µs. Components designed for protection in this range are therefore tested with impulse-currents of 8/20 µs (This means: Rising a current from 0 to 5kAmp within 8µs then sloping down to 0.1kAmp at 20µs) see diagram below for clarity.
 
Most of the commercially packed surge protectors operate in this bracket; needless to say that is why people believe that “lightning protection” doesn’t work. Protection products in this category must be supported with a proper 10/350 combination pack to ensure lightning protection. The commercial products will only be good for what it was advertised – surges! Remember, all surge protection devices must preferably be replaces after 24 months – the theoretical lifespan of a surge arrestor
 
 

Lightning protection Zones

 
LPZ 0 A                  Direct Lightning Stroke, entire lightning field                ≈100kAmp               Business DB (Class 1 Protection)
 
LPZ 0 B                  Direct Lightning Stroke, partial lightning field                ≈25kAmp                 Household DB (Class 2 Protection)
 
LPZ 1                     Limited Impulse Currents at Zone boundary                 ≈8kAmp                   TV, CCTV (Class 3 Protection)
 
LPZ 2                     Limited Impulse Currents at Zone boundary                 ≈5kAmp                   Appliances (Class 3 Protection)
 
 
Only use and install product with indication of performance like 40kAmp iMax @ 275Volt
 
 
Curve interpretation
 
The total green area represents the energy of a severe direct lightning stroke onto a house, tree, soil, etc.
a.       Green dot 1 represent protection from a LPZ 0 device (in South Africa some manufacturers will denote it as class 1 protection)
b.       Red dot 2 curve area represent the energy absorption of a typical surge device bought over the counter to protect your equipment
 

Typical Surge Protection installation for a household

40 kAmp 10/350 LPZ 0 B (Blue) Arrestor plus 40 kAmp 8/20 LPZ 1 (White) Arrestor. This will normally redirect the average direct stroke onto a premises. Note the graan tag on the left arrestor indicate functionality. The 10/350 hardly ever needs replacement, only on a severe direct strike
 
 
Some myths about lightning
The facts
·    Lightning never strike twice on the same place
The average is 3 times with 7 times not unusual
·    Mirrors draw lightning
The chrome on the mirror can act as a electrical conductor if it is in the “path” of the stroke
·    You must lay flat on the ground in the event of a storm
You can get ≥2000Volt between your feet & head potential difference resulting in a hard shock, even death. Sit down with your feet close to each other. (crunch)
·    You are safe in a car
Not allways100%. If it is an Aluminum body like the new Mazda RX8 you are not magnetically shielded against the radiation. If it is a soft top “convertible car you are still in danger, seek shelter like a bridge and pull over
·   Save on a bicycle, horseback, etc
Very dangerous. You are an antenna. Get off. Get away from the horse and crunch

ALARMAN ALARMS AND ALARM SYSTEMS PRETORIA, JOHANNESBURG, MIDRAND, GAUTENG, SOUTH AFRICA

UPSs are more expensive than inverters, but what you pay is what you get. Most failures of electronic equipment are due to the inconsistency of power supplied by Eskom. UPS power is clean and protects your equipment against high/low voltages, spikes, surges, brownouts and dips. They are the ultimate protection for your expensive equipment. Also ensure that if you opt for backup time, rather than just clean power, make sure your UPS supplies sine wave when running off your batteries.
UPSs are more expensive than inverters or just plain surge protection, but what you pay is what you get. Most failures of electronic equipment in South Africa, are due to the inconsistency of power supplied by Eskom. UPS power is clean and protects your equipment against high/low voltages, spikes, surges, brownouts and dips. They are the ultimate protection for your expensive equipment. Also ensure that if you opt for backup time, rather than just clean power, make sure your UPS supplies sine wave when running off your batteries.