It is an electrical contractor’s nightmare to be told that the wiring according to the electrical inspection folk is not according to standard requirements. In the case described here the choice was between ripping out and replacing conductors–or proving that temperature rise of the wiring was within acceptable limits for the current load.
The very idea of unpicking the wiring in a large supermarket, in country Victoria following a ‘failed’ report by Energy Safe Victoria would have been enough to cause premature retirement of the electrical contractor. Fortunately, a neat technical solution presented itself in the use of a series of small, compact loggers, with infrared interrogation, allowing remote download of critical data. Power Parameters Pty Ltd, a company specialising in electrical instrumentation for electrical engineers and contractors provided instrumentation and advice on the data collection project. Separate loggers for temperature and current, using current clamp-on sensors were employed to prove that the installation answered to standard requirements. Fortunately for the contractor (as well as the client, who would have otherwise experienced a level of business interruption) the measurement program proved that the wiring supported its loads adequately.
The apparatus used was part of the full suite of Hioki LR5000 series data loggers. These are versatile and cover temperature, humidity, millivolt and milliamp signals appropriate to transducers in control instrumentation environments and AC current. For the above application temperature and current were the parameters chosen.
Hioki LR 5100 Series RMS current recorder
They provide for temperature and humidity (-40°C to +85°C; 0% to 100% RH), instrumentation (0-20 mA), DC voltage (to a maximum of ±50 volt) and AC current data logging (to a maximum of 1000 amps), and have an overall data storage capacity of 60,000 points. They are widely applied for field monitoring including transport vehicles and HVAC service and commissioning.
Measuring only 8 x 6 cms and less than 3 cms thick they were easily deployed in tight situations encountered in the supermarket installation. Battery operated by AA batteries, data was permanently preserved and in the event that batteries were to discharge, storage operations would be able to be continued by replacing batteries within thirty seconds. The data loggers were, where appropriate, conveniently mounted close to the required monitoring locations by means of a magnetic mount and strap, and relocatable wall brackets.
The sampling intervals can be chosen in the range from 1 second to 60 minutes between data points. Sampling modes selectable are ‘instantaneous value’ and ‘statistical value’. The statistical value recording method allowed the capture of minima and maxima within the sampling window selected. Bundled software was provided to furnish graphical and numerical displays. The latter feature was particularly important in the supermarket wiring monitoring program as flashcard data storage or, as in this case, transfer to PC provides very large data capture schemes.
Recorded data was transferred directly to a PC but other options include the Hioki LR5092-20 Data Collector. In the latter case the data collector can interrogate up to 16 data loggers via its optical infrared port as well as poll the instruments for set-up parameters and information. Its stored data can be transferred to a SD card with maximum storage of 32 GB or to a PC.
Computer data download options: directly or via IR data collector
IR data collector