DMN_34-523 - Distribution Technology Home - Eskom

Task Manual 

Group Technology 

Title: 

ISOLATOR: KARG, LEL AND 

SPEEDCRAFT 

TYPE: SINGLE PHASE CUT- 

OUT 

RATING: 11kV-22kV; 400A- 

1600A 

MODE OF OPERATION: 

HAND OPERATED 

Unique Identifier: 34-523 

Part 

11 - Maintenance 

Area of Applicability: Distribution Engineering 

Documentation Type: 

Task Manual 

Revision: 1 

Total Pages: 19 

Next Review Date: January 2022 

Disclosure Classification: 

Controlled Disclosure 

Compiled by 

Approved by (SCOWT SC Chairperson) 

Kevin Layley 

Advisor 

Ajith Persadh 

Senior Advisor 

Date: 21/11/2011 Date: 21/11/2011 

Functional Responsibility 

Authorized by 

Colin Smith 

DTEP Manager 

Prince Moyo 

Power Delivery Engineering GM (Acting) 

Date: 28/11/2011 Date: 18/12/2011 

B Morrison / January 2012 / Rev 1 

ESKOM COPYRIGHT PROTECTED

DOCUMENT CLASSIFICATION: CONTROLLED DISCLOSURE 

ISOLATOR: KARG, LEL AND SPEEDCRAFT Unique Identifier: 34-523 

TYPE: SINGLE PHASE CUT-OUT 

Type: 

DMN 

RATING: 11kV-22kV; 400A-1600A 

Revision: 1 

MODE OF OPERATION: HAND OPERATED 

Page: 2 of 19 

Content 

Foreword ........................................................................................................................................................ 3 

Introduction .................................................................................................................................................... 5 

1 Scope .................................................................................................................................................. 5 

1.1 Purpose ....................................................................................................................................... 5 

1.2 Applicability .................................................................................................................................. 5 

1.3 Roles and Responsibilities .......................................................................................................... 5 

2 Normative / Informative references ..................................................................................................... 6 

2.1 Normative .................................................................................................................................... 6 

2.2 Informative ................................................................................................................................... 6 

3 Definitions and abbreviations .............................................................................................................. 6 

3.1 Definitions .................................................................................................................................... 6 

3.2 Abbreviations ............................................................................................................................... 7 

4 Requirements ...................................................................................................................................... 7 

4.1 First and Second Line Maintenance ............................................................................................ 7 

4.2 Specialist maintenance ................................................................................................................ 7 

4.3 Modification ................................................................................................................................ 14 

5 Testing ............................................................................................................................................... 14 

6 Related/Supporting Documents ........................................................................................................ 14 

6.1 Related Documents ................................................................................................................... 14 

6.2 Forms and Records ................................................................................................................... 14 

7 Spares ............................................................................................................................................... 14 

Annex A - Isolator Maintenance Checksheet .............................................................................................. 15 

Annex B - Impact assessment ..................................................................................................................... 16 

Page 

ESKOM COPYRIGHT PROTECTED 

When downloaded from the DT WEB, this document is uncontrolled and the responsibility rests with the user 

to ensure it is in line with the authorised version on the WEB.




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Foreword 

This task manual was compiled to conform or align with NRS 082, NRS 090 and NRS 090-1-1 in ensuring 

that equipment in our network are maintained. 

KARG, LEL AND SPEEDCRAFT ISOLATORS 







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Revision History 

This revision cancels and replaces revision no 0 of document no. DWN_34-523 

Date Rev. Clause Remarks 

Jan 2012 1 - Compiled By: KC Layley 

- 

Reformat only. No content change. 

Document number changed to DMN_34-523 

Jan 2008 0 

Compiled By: DM Ntombela 

The template / format and ref. number changed; 

Revision date 

• Normative references updated; 

2, 3 • Definitions and abbreviation updated; 

• Re-numbered all the titles and added more information; 

• Included Revision History information; 

• Included impact assessment form; and 

• Reference number changed to DWN 34-523 

April 2004 0 Compiled By: EO Mutloane 

Original issues as SCSINAAJ4 

Acceptance 

This document has been seen and accepted by: 

Name 

Designation 

P Moyo 

Power Delivery Engineering GM (Acting) 

C Smith 

A Persadh 

DTEP Manager 

Care WG Chairperson 

This task manual shall apply throughout Eskom Holdings Limited, its divisions, subsidiaries and entities 

wherein Eskom has a controlling interest. 

Development team 

This task manual was previously prepared by: 

J.H.Coetzer 

G Kruger 

D.M.Ntombela 

C.D.Smith 

A.M.Jacobs 

O.E.Mutloane 

J.J.Olivier 

A.M.Stoffberg 

O.Turner 

This task manual was revised by: 

DM Ntombela 







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Introduction 

This task manual was compiled to document the tasks procedure in maintaining ISOLATORS to ensure that 

maintenance tasks are carried out in a safe manner where risks and hazards are analysed and mitigating 

measures are incorporated. 

This task manual is the revision of isolator document which was initially compiled and titled “ISOLATOR: 

KARG, LEL AND SPEEDCRAFT; TYPE: SINGLE PHASE CUT OUT, Rating: 11kV-22kV, 400A-1600A, 

MODE OF OPERATION: HAND OPERATED” to formalize the procedures of performing tasks when 

carrying maintenance tasks out. The document includes the latest updates in information, format, safety 

precautions and diagrams to make it more user-friendly. 

Keywords 

Top contact; Bottom contact; Fuse element; and Insulator 

Bibliography 

Not applicable. 

1 Scope 

1.1 Purpose 

The purpose of this task manual is to standardise maintenance instruction on KARG, LEL AND 

SPEEDCRAFT ISOLATORS type SINGLE PHASE CUT OUT, rated at 11kV-22kV; 400A-1600A with a 

manually operated MECHANISM. 

1.2 Applicability 

This document shall apply throughout Eskom Distribution division and contractor employed by distribution. 

1.3 Roles and Responsibilities 

1.3.1 Plant Managers shall be responsible for: 

a) Ensuring that equipment job plans are available and issued for specific maintenance. 

b) Ensuring that the maintenance feedback information that is available in the maintenance 

management system is analysed. 

1.3.2 Each Field Services Manager shall be responsible for: 

a) Ensuring that staff carrying out maintenance tasks is trained, competent and authorized to 

perform maintenance on the specific equipment; 

b) Ensuring that instructions are implemented and adhered to and equipment is maintained in 

accordance to relevant work instructions. 

c) Ensuring that the maintenance feedback information / data is captured and recorded into the 

system for future maintenance planning. 







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2 Normative / Informative references 

Parties using this document shall apply the most recent edition of the documents listed below: 

2.1 Normative 

The following documents contain provisions that, through reference in the text, constitute requirements of 

this task manual. At the time of publication the revisions indicated were valid. All standards are subject to 

review and parties to agreements based on this work instruction are encouraged to investigate the 

possibility of applying the most recent revision of the documents listed below. Information on currently valid 

national and international standards may be obtained from the Information Centre at Megawatt Park and 

Technology Standardization Department. 

Occupational Health and Safety Act and Regulations (OHSAct); 

NRS079-1: Mineral Insulating Oils 

DST_32-332: Oil spill clean-up and rehabilitation. 

EPL_32-94: Environmental management policy. 

DST_34-1710: Personal protective clothing manual. 

DPC_34-444: Procedure for the application and maintenance of portable earthing gear. 

DPC_34-227: Procedure for the identification of risk prior to the commencement of work. 

DPC_34-908: Procedure for barricading. 

Manufacturer`s manual. 

OPR 6204: Rev 5, Operating regulations for high voltage systems 

2.2 Informative 

DST_34-4, Procedure For The Preparation And Administration Of Distribution Standards 

Manufacturers manual 

3 Definitions and abbreviations 

3.1 Definitions 

All definitions in NRS040 and OHSAct 85 of 1993 are applicable. 







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3.2 Abbreviations 

CDP: Career Development Programme; 

PTO: Principal Technical Officer; 

STO: Senior Technical Officer; 

TO: Technical Officer; and 

CCC: Change Control Committee 

4 Requirements 

4.1 First and Second Line Maintenance 

a) Insulators shall be inspected for chips and breakage. A maximum of 20% of chipped or broken 

sheds is permitted on an insulator. Chips or breaks shall be painted with Glyptol at the earliest 

opportunity. 

b) Pollution levels on insulators shall be monitored. An anti-pollution medium shall be applied in 

accordance with local requirements. 

c) Check to ensure that all three phases are properly closed and correctly aligned. 

d) Check for hot connections. 

e) The operating label shall be securely mounted and shall be legible from the operating position. 

f) All metal work shall be checked for corrosion or rust. 

g) The earth straps shall be in a good condition and effectively connected. 

NOTE: All defects found are to be reported to the Work Management Centre with the work order feedback. 

4.2 Specialist maintenance 

4.2.1 Pre-planning 

4.2.1.1 Spares and Materials 

a) Approved Contact grease 

b) Approved Lubrication grease. 

c) Approved electrical cleaner. 

d) Sterilized cloth. 

e) Spare fuses 

f) Plastic scourer. 







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4.2.1.2 Tools and Equipment 

a) Standard set of tools; 

b) Grease gun; 

c) Cleaning tray; 

d) Fuse holder; 

e) Fuse element (different Amperages); 

f) Insulator; 

g) Ductor tester; and 

h) D C clip-on ammeter. 

4.2.1.3 Personal Protective Equipment 

All personal protective equipment shall be in accordance with DST_34-1710 and those identified by risk assessment 

(DPC34-227). 

a) Overall 

b) Hard hat 

c) Safety boots 

d) Fall Arrest System 

e) Barrier cream. 

f) Gloves 

4.2.2 Safety and preparation 

a) Isolate and earth the line in accordance with NRS040. 

b) Erect scaffolding (where required). 

c) Ensure all tools, equipment and materials are placed inside the barricaded area where they will 

not hinder or obstruct any worker. 

d) Environmental hazards shall be removed in accordance with DST_32-332. 

e) Ensure that isolator is isolated in terms of NRS040 and where applicable any LV protection supply 

is switched OFF before commencing with the next steps. 

4.2.3 Isolator Maintenance 

Risk assessment and critical task analysis shall be done in accordance to DPC_34-227 and approved safe 

work procedures before the commencement of work. 







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4.2.3.1 Replacing of the burnt replaceable fuse element 

a) Disengage the fuse holder by pulling the fuse holder from the latch at the top contact with a link 

stick (see figure 1). 

Figure 1 

NOTE: Before opening the isolator ensure that it is under no load condition by opening the circuit-breakers on either 

the load side or supply side of the isolator. 

b) Disengage the bottom part of the fuse holder by lifting the fuse holder a little bit so as to 

disconnect from the hinge at the bottom contact (see figure 2). 

Figure 2 

c) After bringing down the fuse holder, unscrew the fuse holder contact tip at the top so as to access 

the replaceable fuse element (see figure 3). 

d) Pull out the fuse element remaining part (see figure 3). 

e) Loosen the fuse element holding bolt at the bottom contact and remove the old fuse element tail. 







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Figure 3 

f) Inspect the top and bottom contact-points for burn marks, overheating and / or oxidation (refer to 

figures 1&2 and see figure 4). 

g) Where arcing contacts are in place examine them and the arc shields for excessive wear and 

burning (refer to figure 3 above). 

h) Fit the washer onto the fuse element, insert the element into the fuse holder and screw the 

contact tip onto the holder so as to hold the fuse element in position (refer to figure 3 above) and 

see figure 4). 

Figure 4 

i) Straighten or hold the fuse holder in a charged position, pull the element tail and engage it on or 

around the holding bolt and tighten it. 

j) Raise the fuse holder assembly with a link stick, engage it bottom first into the isolator hinge 

(pivot) and push the other end (unhinged or contact tip end) into the top contact (refer to the main 

pictures under “Foreword” above). 

NOTE: Ensure that solid contact is made with the top part / fuse holder contact tip. 

4.2.3.2 Removal of isolator from the structure (if required) 

NOTE: Ensure that both sides of the isolator have been earthed as per NRS040. 

a) Loosen and remove the bolts / nuts connecting the jumper onto the top contact of the isolator and 

remove the jumper from the isolator (see figure 5). 







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Top and bottom 

jumper connecting 

nuts 

Figure 5 

b) Tie the jumper to the structure or to the isolated and earthed line to prevent it from swinging into 

any live apparatus in the vicinity or interfering with the work. 

c) Loosen and remove the bolts / nuts connecting the jumper onto the bottom contact of the isolator 

and remove the jumper (refer to figure 5 above). 

d) Tie the jumper to the structure or to the isolated and earthed line to prevent it from swinging into 

any live apparatus in the vicinity or inferring with the work. 

e) Support the isolator, loosen and remove the bolts securing the isolator onto the structure and 

remove the isolator (see figure 6). 

Isolator mounting 

bracket with 

bracket securing 

Support 

insulator 

Figure 6 

f) Make provision for the isolator to be brought down safely by using either a rope or a second 

person to help in lowering the equipment to ground level. 

4.2.3.3 Inspection of the top contacts 

a) Check the condition of the top contacts and clean the contacts using the plastic scourer and 

electrical cleaner (see figure 7). 

b) Examine the both contact assemblies for burn marks, carbon built-up, excessive wear and or 

pitting (see figure 7). 







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c) Examine the tensioning springs for tension loss (refer to figure 4 and see figure 7). 

Figure 7 

d) Check that the nuts securing the contacts to the support insulators are tight. 

e) Check that the link latch tension is in order (refer to figure 4 above). 

f) Check, clean and grease all the pins. 

g) If any of the above mentioned parts are faulty replace them with new ones. 

NOTE: If the contacts are permanently fixed to the insulator then the whole isolator set must be replaced. 

4.2.3.4 Inspection of the bottom contacts 

a) Check the condition of the bottom contact assemblies (refer to figure 2 above). 

b) Examine the contact assembly for burn marks, excessive wear, spring tension loss and or pitting. 

c) Clean the contacts using the plastic scourer and electrical cleaner. 

d) Check that the bolts / nuts securing the contacts to the support insulators are tight (see figure 8). 







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Figure 8 

e) Check that the link / isolator is in alignment when fully closed and re-align if necessary. 

f) Check that the link / isolator hinge is in order (refer to figure 8 above). 

g) Check, clean and grease all pivoting pins. 

h) If any of the above mentioned parts are faulty replace them with new ones. 

NOTE: If the contacts are permanently fixed to the insulator then the whole isolator set must be replaced. 

4.2.3.5 Inspection of the insulators 

a) Check the support insulators for tracking and or severe pollution build-up. 

b) Test the support insulator for cracks by using "RING TESTING". 

c) Check the support insulator for strength. 

NOTE: Some insulators may be porous due to age and that may cause problems for operators. 

d) If there are problems with support insulators, the whole isolator set shall be replaced. 

e) Clean the insulators thoroughly with an approved cleaner and the scourer. 

4.2.3.6 Refitting new isolator onto the structure (if required) 

a) Safely lift the isolator up to the mounting position by using either a rope or a second person to 

help. 

b) Place the isolator onto the structure, align the isolator bracket / base to the mounting holes, insert 

the securing bolts and tighten them. 

c) Untie the jumper of the top contact from the structure or the isolated and earthed line. 

d) Ensure that the jumper connection ends / lugs and clamp are clean, place the jumper onto the 

isolator top contact terminal connection hole, insert the connection bolts and tighten it. 

e) Untie the jumper of the bottom contact from the structure or the isolated and earthed line. 

f) Ensure that the jumper connection ends / lugs and clamp are clean, place the jumper onto the 

isolator bottom contact terminal connection hole, insert the connection bolts and tighten it. 







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g) Where all three phases are to be replaced repeat steps a) to f) above on the remaining phases. 

4.2.3.7 Mechanism 


4.2.3.8 Adjustments 

Not applicable 

4.3 Modification 

Not applicable 

5 Testing 


6 Related/Supporting Documents 

6.1 Related Documents 

a) Critical task analysis: 

1. High Voltage Operating; and 

2. Work with/on Extension/Single Ladders. 

b) Training module; 

c) Relevant Manufacturers manual. 

6.2 Forms and Records 

The attached report shall form the record of work done. 

The completed report must be returned to the Work Co-ordinator together with the work order and a copy to 

the Technical Services Group. 

7 Spares 

Refer to 4.2.1.1 above 







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Annex A - Isolator Maintenance Checksheet 

(Normative) 

ISOLATOR MAINTENANCE CHECKSHEET 

Substation Name: _________________________ 

Panel: __________________________________ 

Customer Order Number: ___________________ 

Maintained by: ____________________________ 

Isolator make: ___________________________ 

Type: __________________________________ 

Serial Number: ___________________________ 

Isolator Rating: ___________kV _________ Amp 

Date: ___________________________________ 

Task Task Done Comments 

Yes/No 

1. Remove jumper clamps and measure contact resistance 

before maintenance. 

2. Remove completely strip and maintain male arms 

3. Remove completely strip and maintain female contacts. 

4. Maintain turning head/transfer contact assembly 

5. Maintain inter-phase rods 

6. Maintain mechanism box 

7. Clean and inspect post insulator 

8. Maintain jumper clamps 

9. Measure after-maintenance contact resistance. 

10. Refit the jumpers and re-align main contact arms 

11. Functional test (open and close isolator) a few times to 

check alignment. 

12. Check for rust 

13. Torque bolts in accordance with maintenance instruction 

manual 

14. Lubricate all parts correctly. 

15. Maintain and refit the jumper clamps 

Measure 

Point 

Recommend 

Readings 

Before 

Maintenance 

Red Phase White Phase Blue Phase 

After 

Maintenance 

Before 

Maintenance 

After 

Maintenance 

Before 

Maintenance 

After 

Maintenance 

A 

B 

C 

D 

E 

F 

G 

H 

I 

J 

Note: If the after-maintenance reading is more than the before -maintenance reading, then establish the reason for it 







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1 Guidelines 

Annex B - Impact assessment 

(Normative) 

o All comments must be completed. 

o Motivate why items are N/A (not applicable) 

o Indicate actions to be taken, persons or organisations responsible for actions and deadline for 

action. 

o Change control committees to discuss the impact assessment, and if necessary give feedback to 

the compiler of any omissions or errors. 

2 Critical points 

2.1 Importance of this document. E.g. is implementation required due to safety deficiencies, 

statutory requirements, technology changes, document revisions, improved service quality, 

improved service performance, optimized costs. 

Comment: Statutory requirements and or document revisions 

2.2 If the document to be released impacts on statutory or legal compliance - this need to be 

very clearly stated and so highlighted. 

Comment: No impact on statutory or legal compliance and mainly document revisions 

2.3 Impact on stock holding and depletion of existing stock prior to switch over. 

Comment: N/A - No new equipment or item need to be acquired for implementation of this document. 

2.4 When will new stock be available 

Comment: N/A –see 2.3 above. 

2.5 Has the interchange ability of the product or item been verified - i.e. when it fails is a straight 

swap possible with a competitor's product 

Comment: N/A – It is a maintenance document and also see 2.3 above. 

2.6 Identify and provide details of other critical (items required for the successful 

implementation of this document) points to be considered in the implementation of this document. 

Comment: Consult / Refer to DST_34-1454 for routine inspections when implementing the document. 

2.7 Provide details of any comments made by the Regions regarding the implementation of this 

document. 

Comment: None. 







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3 Implementation timeframe 

Annex B 

(continued) 

3.1 Time period for implementation of requirements. 

Comment: N/A – No technical changes were made to this document. 

3.2 Deadline for changeover to new item and personnel to be informed of DX wide change-over. 

Comment: None. 

4 Buyers Guide and Power Office 

4.1 Does the Buyers Guide or Buyers List need updating 

Comment: NO. 

4.2 What Buyer’s Guides or items have been created 

Comment: NONE. 

4.3 List all assembly drawing changes that have been revised in conjunction with this 

document. 

Comment: NONE 

4.4 If the implementation of this document requires assessment by CAP, provide details under 5 

Comment: N/A – The revision requires no new equipment. 

4.5 Which Power Office packages have been created, modified or removed 

Comment: NONE: 

5 CAP / LAP Pre-Qualification Process related impacts 

5.1 Is an ad-hoc re-evaluation of all currently accepted suppliers required as a result of 

implementation of this document 

Comment: NO 

5.2 If NO, provide motivation for issuing this specification before Acceptance Cycle Expiry date. 

Comment: N/A – The document doesn’t specify but stipulates the maintenance procedures on the existing 

equipment. 







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Annex B 

(continued) 

5.3 Are ALL suppliers (currently accepted per LAP), aware of the nature of changes contained in 

this document 

Comment: N/A – The specification document is the document supplied to the suppliers not this one. 

5.4 Is implementation of the provisions of this document required during the current supplier 

qualification period 

Comment: Yes – This is the revision of document that is presently being implemented and requires no 

change to the supplier’s qualification period. 

5.5 If Yes to 5.3, what date has been set for all currently accepted suppliers to comply fully 

Comment: N/A – see 5.3 above. 

5.6 If Yes to 5.4, have all currently accepted suppliers been sent a prior formal notification 

informing them of Eskom’s expectations, including the implementation date deadline 

Comment: N/A – see 5.4 above. 

5.7 Can the changes made, potentially impact upon the purchase price of the 

material/equipment 

Comment: N/A – No new material / equipment is required. 

5.8 Material group(s) affected by specification: (Refer to Pre-Qualification invitation schedule for 

list of material groups) 

Comment: N/A – No new material is required. 

6 Training or communication 

6.1 State the level of training or communication required to implement this document. (E.g. 

none, communiqués, awareness training, practical / on job, module, etc.) 

Comment: Practical / On job and training module. 

6.2 State designations of personnel that will require training. 

Comment: TSO, PTO & STO. 

6.3 Is the training material available Identify person responsible for the development of 

training material. 

Comment: Yes – DT- Training is revising earthing related training manual which will address the changes in 

this document. 







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Annex B 

(continued) 

6.4 If applicable, provide details of training that will take place. (E.G. sponsor, costs, trainer, 

schedule of training, course material availability, training in erection / use of new equipment, 

maintenance training, etc). 

Comment: Safety and Maintenance training. 

6.5 Was Training & Development Section consulted w.r.t training requirements 

Comment: Yes. 

7 Special tools, equipment, software 

7.1 What special tools, equipment, software, etc will need to be purchased by the Region to 

effectively implement 

Comment: NONE. 

7.2 Are there stock numbers available for the new equipment 

Comment: N/A – No new equipment is required. 

7.3 What will be the costs of these special tools, equipment, software 

Comment: N/A – No new equipment is required. 

8 Finances 

8.1 What total costs would the Regions be required to incur in implementing this document 

Identify all cost activities associated with implementation, e.g. labour, training, tooling, stock, 

obsolescence 

Comment: 

No costs other than the training will be incurred by the regions and this will depend on the arrangements 

made for training i.e. Training is held regionally or nationally. 

Impact assessment completed by: 

Name: Ajith Persadh 

Designation: Senior Advisor, Engineering Processes, IARC

DMN_34-523 - Distribution Technology Home - Eskom

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