Technical Bulletins
Compulsory Specification
As from 24th January 2001 SABS 1507 became a compulsory specification. This means that all low voltage electric power cables installed in South Africa must comply with the stipulated requirements in SABS 1507.There could be serious repercussions for any organisation that deliberately or unintentionally sells or installs non-compliant cable.ICS 29.060.20Folder/Omslag VC 8075.
Marking of Cables
Some customers mistakenly order Blue, Red or White stripe cables. Given that SABS 1507 is compulsory (see Technical Bulletin 02) it is mandatory for such cables to have the following construction characteristics
Numbering of SABS Specifications
In designing and producing cables, CBI-electric: african cables always subscribes to the latest version of the applicable specifications. The new numbering approach adopted by the SABS in 2000 is potentially confusing and this bulletin serves to clarify the matter.
SANS Standards
The Standards Division of the SABS has changed its name and will henceforth publish standards under the banner of Standards South Africa. All of their national standards are being redesignated as SANS (South African National Standard) standards
Volt Drop
This technical bulletin has been created to explain the concept of volt drop to customers and provides an example on how to calculate volt drop from volt drop ratings given in African Cables Technical Datasheets.
Application of PVC and ZEROTOX in cables
PVC insulated, bedding and sheathed cables are inherently flame retardant. In a fire situation normal PVC cables will burn only with difficulty, but in certain conditions, for example when cables are installed vertically, PVC will burn and can cause a fire to spread rapidly throughout a building or the cable basement of a substation or power station. A disastrous fire at La Spezia pow
Tests after installation - SANS 97
SANS 97: Electric cables-Impregnated paper-insulated metal-sheathed cables for rated voltages 3.3/3.3 kV to 19/33 kV (excluding pressure assisted cables)Voltage test after laying, jointing and terminating for cables manufactured to this standard as stipulated in Appendix A.3.3.
Tests after installation - SANS 1507
SANS 1507: Electric cables with extruded solid dielectric insulation for fixed installations(300/500 V to 1 900/3 300 V)Voltage test after laying, jointing and terminating for cables manufactured to this standard as stipulated in Appendix C.3
Tests after installation - SANS 1339
SANS 1339: Electric cables-Cross-linked polyethylene (XLPE) insulated cables for rated voltages 3.8/6.6 kV to 19/33 kVVoltage test after laying, jointing and terminating for cables manufactured to this standard as stipulated in SANS 10198: Part 13 clause 5.5
Tests after installation - IEC 60840
IEC 60840 ed 3: Power cables with extruded insulation and their accessories for rated voltages above 30 kV (Um = 36 kV)Recommended voltage tests after laying, jointing and terminating of cables manufactured to this standard based Clause15.
Compression forces
There is much uncertainty about the permissible mechanical loads that cables can withstand where they pass under a road or other load bearing surface. To quantify the risk we offer the following information.
Accessory code interpretaion
SAP Accessory Code Interpretation - Technical Bulletin No. 14
Porcelain busing development
There has recently been a change to the profile of porcelain bushings used on the CBI-electric: african cables Outdoor seating ends. This bulletin serves to clarify the need and the consequences of the change.
Compulsory specification - VC 8077
As from 15 October 2003 SANS 97 and SANS 1339 became compulsory specifications. This means that all medium voltage electric power cables installed in South Africa must comply with the stipulated requirements in SANS 97 and SANS 1339.There could be serious repercussions for any organisation that deliberately or unintentionally sells or installs non-compliant cable.
Moisture in paper cables
Paper insulation is known to be sensitive to moisture hence the application of a lead covering. The majority of paper insulated cable failures are due to the ingress of moisture through the cable ends. This bulletin serves to give some guidelines in the prevention of this problem.
Interaction between cable Oil and XLPE
Cable oil is found in fluid filled cables and could come in contact with XLPE cables at transition joints. Literature claims that cable oil is “fairly” compatible with XLPE. This bulletin serves to quantify the effect of cable oil on XLPE.
Lead free stabilisers for PVC Cables
Polyvinyl Chloride (PVC) is known to degrade upon heating. Stabilizers are used to limit the degradation. Traditionally stabilizers containing Lead (Pb) were used. CBI-electric: African Cables now offers Lead Free PVC as the norm. This bulletin serves to highlight the benefits of switching to lead free stabilizers.
Prevention of termite attack for PVC cables
Prevention of termite attack on cables has mainly been accomplished by the incorporation of suitable insecticides in the sheath of the cable. For environmental reasons, the commonly used insecticide called Lindane was abandoned and replaced by an alternate from Sorex UK under the tradename of Termitex TC10. This bulletin serves to highlight the use of Termitex TC10 in CBI-electric: african cables Termite repellent cable sheaths.
Thermal Time Constant
Theft Prevention
Proof of ownership is the biggest hurdle to overcome when trying to convict a person of cable theft. Here we detail our theft prevention initiative which started in May 2009.
Cable Strapping Using Glass Fibre Filament Tape
This bulletin provides guidelines for the application of reinforced glass fibre polypropylene filament tape for strapping cables together, particularly single core cables in trefoil formation. This is essential to ensure that cables stay in formation during short-circuit forces so as to minimise circuit disturbance and damage.
Purpose of Bentonite Mix in Cable Ducts
This bulletin provides information on the purpose of inserting bentonite mix into cable pipes or ducts that are particularly installed under road and railway crossings. Failure to fill the air space between the cable and duct will result in increased thermal resistance and if the current rating of the cable is not derated accordingly, overheating and damage to the cable insulation will occur resulting in premature cable failure.
The use of XLPE in place of PVC insulation for LV cables
This bulletin provides a table of technical facts that may justify the use of XLPE insulated low-voltage cables (600/1000V) instead of PVC insulated cables. Both types of insulation are allowed in the compulsory specification, SANS 1507, with part 3 covering PVC insulation and part 4 covering XLPE insulation.
UV Stabilisation Rev1
There is much uncertainty surrounding UV Stabilisation. Very few specifications are explicit enough. No product offers 100% UV resistance. There will always be some degradation. This can range from a loss of surface gloss to cracking of the polymer. To help customers choose a product, which is fit for purpose, we offer the following information. The “full” UV Protection means it matches the life expectancy of the cable.
