Electrical Fault Investigations

Our Engineers and Equipment

ElectricalCerts operating companies own sophisticated test equipment, capable of analysing faults that would remain undetected by most other test equipment. Our highly-qualified and experienced test engineers, trained in its operation, are able to travel throughout the UK and deal with any problem that is proving too complex for conventional analysis.

A Case in Point

The Ministry of Defence briefed ElectricalCerts (Southern Division) to investigate a possible in-rush surge current created when power was restored to an Uninterruptible Power Supply (UPS) unit located on one of a number of its sites, all of which were experiencing the same problem. We recommended that this type of surge tripping required the use of a Mavowatt 45 to help identify a problem that was beyond the range of most conventional multi-meters. The graph shows how the Mavowatt 45 captured the resultant in-rush current 'spikes'. The spikes were causing the existing BS EN 60898 16 amp Type 'C' overcurrent protective device to trip under start-up load conditions.

Our report continued: '...it is apparent from the results that, at certain times during its operation, the UPS is creating a fairly heavy in-rush current which is probably caused by the inverter and transformer units within the UPS, during their start-up sequence. Under normal supply circumstances, the 16amp "Type C" circuit breaker selected for overcurrent protection should be more than capable of protecting the designated load. However, the inclusion of the UPS device would appear to be "pushing" the breaker past its operating parameters. The overcurrent protective device is a 16amp "Type C" circuit breaker which is designed to cope with general purpose loads. A more suitable device would be the "Type D", designed to cope with high in-rush current loadings.
ElectricalCerts have worked with the Ministry of Defence on Complex Electrical Fault Investigations

'.It would be well worth your time and effort to run further tests at your offices, replacing the "Type C" device with a "Type D". This would prove conclusively that a change of device would eliminate the problem.'

Conclusion

In the event, our advice was followed and the problem was solved.

Costs

For most investigations, it can be extremely difficult to estimate the time that will be required to resolve a particular problem. Our normal practice is to ask the customer to commit to no more than an exploratory visit in the first instance; the engineer would then indicate a best and worst cost estimate.