Specification of high performance Electrical Protection Systems

Electrical protection comes in many forms from fairly standard RCD/RCBO panels and earth line monitoring equipment used for upgrade and maintenance in the industrial/commercial sphere, through to high end Rail and MOD situations where we have gained the necessary approvals through long-term experience and technology.

Typically, modular earth leakage protection units come complete with overload and short circuit protection while many are also approved by Network Rail for use in DC Electrified areas and feature sold state electronic circuitry for stability and immunity from spurious tripping, with different permutations of rating in each voltage range. Standard units are usually in steel, enclosures with RCD test button and MCB toggle at the front.

For ourselves these devices run from the Multiway FDB2 modular panel through the FDB11 at 230V for general purpose building renovation and replacement projects, and the FDB13, FDB15 and FDB19 3 phase 400V units for new build installations. Also in the family is the FDB27 MOD spec unit for aircraft or army hangers, new build and replacement installations.

Sometimes a panel builder will want to incorporate our components into their own system – consequently it is important to them to have access to the same range of panel mounting devices. As experienced specialists in the sphere of AC power protection we offer a wide range of these panel mounting components and standard enclosed units for this purpose – but of course we also have the technology to configure custom panels for protected power on remote airfields, in hangers, on pontoons or in fixed dock situations.

By the very nature of the custom panel building process we suggest a detailed initial conversation with your panel builder to understand what the specification calls for.

The FDB2 RCBO unit is a multi-way housed earth fault protection system which shares DC immune technology with its smaller sister unit the FDB11. FDB2 offers 2 way, 3 way and 4 way options as standard with approval by Network Rail for use in DC electrified areas where it provides general purpose earth leakage protection, including overload and short circuit protection, for AC equipment without the problems of nuisance tripping associated with DC induced currents. This is important in nearby offices, retail outlets and café/restaurants, car parking machines and charging stations for example.

Both AC and DC types of panel mounting components are available to multi-range protection levels including pre-set and user adjustable types. Where appropriate it is important to use solid state circuitry that offers immunity to voltage transients and DC components. For visual monitoring we suggest a panel meter and a portable RCD test set for functional checking.

Naturally there are many well proven standard configurations on the market but of course there is often a need for something a bit different and that is where the expertise of your panel builder comes into play. Whether you are looking for a DC immune device for a rail related installation or an IP 66 three phase unit a company such as FDB Electrical can custom build to meet specific needs – for land based, shore line, ship installation, hangers, workshops, industrial units, and institutions.

One such application is the Monorail Mass-Transit in Singapore where our EFU50 DC protection units have been used. These units protect in-station equipment on the DC contactless charging system where it monitors the DC circuit for earth faults and disconnects in the event a fault is detected so as to protect the system from further costly damage and potentially protect personnel from the effects of the fault.

The EFU50 (RIA tested by UK Network Rail) is part of the FDB Optima series of earth fault protection relays (RCD’s) and will detect residual direct current without having to use Hall Effect transducers. It can also be installed to detect when and where an earth fault occurs in a DC wired circuit, thus eliminating costly man hours and down-time in locating system faults.

The EFU50 is designed to react to DC currently only and will reject induced or stray alternating current from 25Hz to 250Hz up to 2 Amps whilst still operating precisely on DC residential current against its preset level. This enables the EFU50 to be used to detect imposed DC current on AC circuits as well as its primary use of DC residual current detection.

We have also supplied the FDB19/STS special-purpose power supply units for use by Royal Marines landing craft. In this case the FDB19/STS is a specially configured version of the standard FDB19 Heavy Duty Adjustable RCCB, designed to be mounted on offshore pontoons that are supplied from shore-based transformers. Once moored, landing craft can plug into the FDB19 and recharge on-board batteries and ancillary equipment. Housed in GRP enclosures the equipment comprises a 60A, 16KA MCCB feeding an electro/mechanically interlocked socket outlet. Electrical protection is provided by means of an EFU15 multi-function RCD and Emguard Earth Continuity Monitor.

Protection for Ground Support Equipment is another specialist protection situation, in this case calling for a range of earth leakage/earth monitoring devices for protection of personnel and plant – for example in RAF/RNAS hangars or other similar military situations where access to protected mains electrical power is required for mobile equipment or for longer term temporary installations. Fortunately, our FDB27 units are designed in accordance with MOD specifications, with more than 100 variants available to suit all types of service applications.

Specification of a custom electrical protection system is an important process which usually requires a careful discussion with the component or system supplier – FDB Electrical are well situated to aid customers successfully through that process.

Further information on FDB Electrical products can be found at http://www.fdb.uk.com/.