Basic PDUs 

Basic PDUs are available in a wide variety of power capacities and many different physical shapes and sizes. They all serve the same basic function of distributing power from a single input point to multiple sockets.


Local Metered PDUs

The safe and efficient delivery of power to IT equipment is an obvious need especially when the IT function is critical to the operation an organisation. The ongoing increase in power consumption in server racks, data closets, network rooms and data centres means that more and more power capacity, more power outlets and consequently more PDUs are required. Since the circuits supplying the power to the IT equipment are of limited capacity it is very important to be able to see whether a circuit has any capacity left before adding new equipment. Overloaded circuits can cause fuses to blow, breakers to trip and a complete loss of IT capability. Metered PDUs contain a local LED Amp Meter or Power Meter which gives immediate information as to the power load on the circuit. This information allows you to judge where best to locate and plug any new IT equipment without disturbing servers or processes which are already running. Power Meters give fine detail of what is happening on any circuit by providing information including real-time voltage, wattage and power factor.

Monitored PDUs go one or two steps further than metered PDUs;

Current monitored PDUs offer real time and historic data on power usage on a manager’s desktop allowing him to see at a glance exactly what current is being drawn from any PDU in the Datacenter at any time – he has the same information as if he were walking around the Datacenter looking at each PDU individually.

Power monitored PDUs work in exactly the same way as Current monitored PDUs but as well as information on current (amps) drawn a view is given of overall power usage - volts, real power, apparent power, power factor and kWatt-hours. As well as providing information on power usage in real time at the rack (very useful for on-site staff working at the coalface), they offer the same information on the desktop of a Datacenter Manager, Facilities Manager etc. Beyond that, Monitored PDUs offer stored and graphed data on power usage, so that it’s possible to observe power usage history and trends, and see for example how close to capacity some circuits are at peak usage times. From this information, it’s possible to reconfigure circuits and rewire to achieve the safest and most balanced loads across all available circuits. Metered PDUs are a very useful tool when moving, adding or changing IT equipment, since the resulting changes in power use are immediately apparent. No software is necessary to use monitored PDUs – they are accessible by IP address just like any other network device. Upper and lower power thresholds can be set, and alarms generated when these limits are approached, reached or breached. Alarms can be generated by email, SNMP trap, XML or local (buzzer) alarm. Some monitored PDUs allow additional functionality, such as the monitoring and reporting of temperature, humidity, airflow, light and sound levels etc. as well as monitoring of electrical power. When multiple metered PDUs are deployed, it’s possible to have their results and reports displayed in individual windows, and or as a concatinated overall log, so that a view of the IT environment as a whole can be viewed. Monitored PDUs usually monitor the whole circuit (or each phase of it’s a three phase PDU) but can monitor power usage at individual socket level if required.





Switched PDUs provide generally the same minute by minute, day by day information on power (and environmental) conditions as metered PDUs but additionally allow a manager to elect to power any socket ON or OFF either immediately on command, or  by a pre-programmed schedule – this can be done over IP or via a serial link.  While Monitored PDUs can provide comprehensive power and environmental information remotely, only a Switched PDU can allow a Data Center Manager to react immediately to alarms by resetting sockets immediately to ON or OFF so as to power down critical equipment in a controlled way, or to power down non-critical equipment allowing critical servers to remain up during low power availability periods. A Server cabinet is usually closed, for security and safety reasons, and as such contains its own microclimate. I Intelligent (Metered, Monitored and Switched) PDUs can be programmed to react to changing conditions within that microclimate, for instance in an overheating situation, more fans can be automatically brought into action, or non-critical machines can be closed down.


 Basic PDUs and Locally Metered PDUs can be clustered so that up to eight PDUs can report to one IP/serial enabled remote power monitoring Current Meter meaing that overall premise wiring and IP address costs are kept to a minimum. The clustered system is ideal for monitoring power in smaller installations and can also monitor and report on climate (environmental - temperature and humidity) conditions. This sytem includes Digital True RMS Current Metering, Remote Power Monitoring, Audible Alarms for  Overloading and other Events  SNMP and Email alarm reports.

Many of the PDUs above contain environmental monitoring – the ability to interrogate sensors and report back on temperature, humidity, airflow, light sound etc. –every aspect of the microclimate in any rack or Datacenter. FCIT also offers a range of stand-alone environmental monitoring units. Our range of Environmental (Climate) Monitoring units include self contained mini units which can be powered by POE (Power over Ethernet) up through 1U Monitoring Units which can support up to 60 sensors. "Sensors" can also include metered PDUs and Switched units, so it is quite possible to mix and match  PDU and Environmental products to achieve a bespoke solution for any application.



A further step in FCIT’s Environmental monitoring offering is a unit with relays which can automatically respond to alarms, by (for instance) switching on or off more fans, activating or de-activating Air Conditioning units or ventilation units, opening doors, triggering audible or visible alarms etc. This means that either the whole microclimate within the rack can be automatically controlled, or that some initial actions can be sanctioned by an on-site unit whilst waiting for human help to arrive.



The cooling of Datacenters can account for a significant percentage of the total energy bill. Air conditioning is normally set to “overcool” (better safe than sorry?) Datacenter temperature is raised massively by the hot air exhausted from Server racks – thus obviously the need for cooling. By fitting a Fan Control system into a rack the airflow inside the rack can be controlled so that the temperature is kept close to the optimum requirement of the servers, but not unnecessarily cool. The knock-on benefit of this is that no more air than is actually needed by the servers to maintain their required operating environment is passed through the rack and so a minimum necessary volume of hot air is expelled to impose cooling load on the Air conditioning units. This offers savings both by reduced usage of rack based fans and more importantly, lowers the ambient temperature of the Datacenter so saving considerable energy on cooling. Reduced fan noise in the Datacenter is a welcome and useful bonus