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Tips To Prevent Your LV Switchboard From Overheating By Comeca Group

Prevent your LV Switchboard from Overheating

LV Switchboards

• Special thanks to Mélanie Oliver at Comeca Group for the kind permission to republish this article

The monitoring of the heat build-up, often carried out by thermography, allows early detection of anomalies that will lead to spurious tripping or even fire and the immobilisation of the installation for a long period. It is therefore a subject that deserves our full attention because it deals with the safety and availability of the installations and therefore the continuity of production.

Thermography is a solution that ensures that there is no abnormal heating of the switchboard during operation.

However, well before its operation, at the time of specification, purchase and installation of the switchboard, there are a few keys factors not to be overlooked.

In the field of high-power, withdrawable, low-voltage switchboards, it is possible to have a positive influence on the future of the installation from the moment of purchase. Similarly, the choice of equipping the switchboard with certain devices allowing easy and safe access to the components to be controlled will make its’ operation simpler and safer.

A good, original design, continuous monitoring and appropriate maintenance are key to the durability and reliability of the electrical panel over the years.

1. Design your LV switchboard according to the IEC 61439-2 standard

A well-designed electrical panel should be chosen, it should be validated in all respects according to IEC 61439-2. Indeed, this standard requires tests and checks to ensure that each component is implemented in accordance with the rules of the standard and that the temperature rise is perfectly controlled, within acceptable limits.

By carrying out these tests, the original manufacturer has the data at its disposal that enables it to produce suitable, reliable and long-lasting low-voltage assemblies, in line with their operating conditions.

Temperature rise tests on an LV switchboard

2. Maintain your LV switchboard regularly

During installation, care should be taken to ensure that the air vents are not obstructed or limited in their effect to ensure natural ventilation of the switchboard.

The cleanliness of the air vents but more generally of the electrical panel should be periodically checked to avoid any degradation of the intrinsic qualities of the assembly. In addition, the forms of internal separation will not be removed, they are the ones which ensure the protection of the personnel during the thermography and maintenance campaigns.

3.Monitor heat build-up by thermography

Thermography campaigns require going as close as possible to, and aiming at, live components. In doing so, the operator will take more risks than during the operation of his switchboard.

In addition to periodic inspections, certain safety features can facilitate or supplement the monitoring of overheating. Discover the safety elements that can be implemented at the time of the initial investment or modernisation of your existing installation.

Easy & Secure Access

Inspection of the cable terminations is a must. Easy access and the width of the cable sheath are criteria to be considered. The position and shape of the downstream power connections are elements that can bring a increased ease of this operation.

For feeders, the possibility of opening the front opening drawer allows all components and all clamping points of the drawer to be seen.

If this option was not chosen at the time of purchase, the starter may have been fitted with a sighting window, which will nevertheless allow some thermal readings to be taken, but in a much smaller sighting area.

Thermographic sighting

The main busbar, which is often placed in the upper position of the switchboard, can also be examined. The main purpose is to check the temperature at the busbar joints and connections. The fewer they are, the fewer points to be monitored.

The roof of the electrical panel must meet certain safety requirements:

• Easy removal of the sheet metal
• Equipment of removable sheets with captive bolts
• Presence of forms of protection

By its’ design, the assembly must facilitate this operation, which is often uncomfortable to carry out because it is high up and close to live elements.

When choosing the LV switchboard, it is therefore important to ensure that it offers a safe and easy access solution for this type of operation.

The power connections on the incoming circuit breaker(s) are also often difficult to access. This is particularly true for switchboards with cable connections from the front. In this case, permanently readable infrared sensors can be offered.

Points of Vigilance for Sighting Devices without Dismantling

For sighting devices without dismantling (arc-proof windows, large arc-proof windows, grids), the solution must allow measurements to be taken without opening the LV switchboard casing and guarantee the protection of the operator during the inspection, thus avoiding the need for reinforced individual protection to protect against the effects of a possible internal arc flash.

The electrical panel can be fitted with these devices on the incoming columns, to monitor the temperature at the main busbar sides or even on the fronts of some withdrawable drawers.

Focus On Viewing Solutions

Polycrystalline sightglasses are the best known solution; they are relatively expensive and offer a fairly narrow viewing surface but promise good internal arc resistance.

Larger sighting solutions of various shapes and sizes are also available. They consist of a honeycomb structure firmly attached to a plastic film. They allow a much better viewing angle and an increased inspection area. Their internal arc resistance is sufficient in many cases and their plastic film does not degrade over time, unlike polycrystals which lose their transparency over part of the spectrum as they age.

In the case of withdrawable drawers, cheaper solutions can be considered, such as the use of Plexiglas or removable metal sheets that allow partial inspection of the interior but with the appropriate individual protection. The use of front opening drawer is the solution allowing a complete inspection of the inside of the drawer but it leads to an increased risk for the operator during the measurement campaign.

Conclusion

In short, a well-designed, well maintained low-voltage switchboard and regular monitoring of its components enable you to prevent the risk of fire resulting from abnormal heating of your installation.

It should be remembered that each intervention requiring the opening of a door or front plate exposes the operator to a greater risk of internal arcing and contact with live parts.

In fact, tests on the behaviour of the electrical panel during an internal arc are always carried out with the enclosure closed and the effects of the arc on the operator are only evaluated outside the LV switchboard during internal arc conditions.

For thermography campaigns, it is necessary that the operator wears adequate individual protection and is trained to follow the appropriate methodology.

Original article can be found here

About Comeca

Our aim is to help your company to improve its performance.

COMECA is also a solid and innovative business partner, with strong knowledge of the major trends in the energy market such as energy efficiency, renewable energy sources and infrastructures for electric vehicles.

COMECA continues to support its established installed base all over the world, while bringing its know-how and expertise in new projects.

To support changes in energy distribution and meet customers’ needs, COMECA offers :

• A « Global Solution » approach that presents important elements of differentiation
• A complete and complementary range of products through its strategic core businesses, providing “package solutions”
• A customised proposal, based on free choice of electrical components brands
• The largest range of original manufacturer switchboards in the market
• A full range of services for your existing COMECA equipment as well as for your new equipment

Power Cable Accessories

To support the installation of Low Voltage Power Cable Systems, Thorne & Derrick stock and supply an extensive range of Cable Accessories to enable to support, jointing, glanding and termination of BS5467 Armoured Cables from leading manufacturers including CMP, Cembre, Ellis Patents and 3M Electrical.

Low Voltage 1000V | Resin Joints | Cable Lugs | Cable Glands | Cable Cleats

Megger TDR1000/3P Handheld TDR For Power Cable Fault Location

Electrical Test Equipment LV MV HV

Handheld TDR for Fault Finding on Cables

Images Courtesy of: Neil Trotter – HV & LV Cable Jointer at Northern Power Grid

Pictured: Megger TDR1000/3P Cable Fault Location Equipment showing an LV underground mains cable fault. Fault location from substation at 104 metres. The images show an open circuit and then an issue 13 metres from point of electricity supply – this cable fault was caused by incorrect cable laying.

The third and fourth images show the cable outersheath has been dented by dolomite during the backfilling of the cable trench.

Megger TDR1000/3P is a compact, hand held time domain reflectometer (TDR) for locating faults on metallic cables – it has a minimum resolution of 0.1 m and a 5 km maximum range depending on velocity factor selected and cable type. The Megger range of Electrical Cable Testing & Fault Location Products are available to purchase via a network of UK Channel Partners or from established hire fleets at competitive daily/weekly hire rates, such as Sunbelt Rentals.

Handheld TDR For Troubleshooting and Locating Faults On Metallic Cables

Megger TDR1000/3P Single Channel Cable Fault Locator

Megger TDR1000/3P

handheld TDR for Power Applications

With built-in blocking filters and fused test leads, the Megger TDR1000/3P Time Domain Reflectometer is a compact, hand held time domain reflectometer for locating faults on metallic cables. It has a minimum resolution of 0.1 m/0.3 ft and a 5 km/15 kft  maximum range depending on the velocity factor selected and the cable type.

Four output impedances are available (25, 50, 75, and 100 Ω) and a velocity factor between 0.2 and 0.99 will meet any cable test requirements.

Megger TDR1000 has a simple auto selection option which together with a 4 way control switch offers an intuitive operation for the user.

• Adjustable display contrast
• Resolution to 0.1 m
• For use on Telecom TNV-3 circuit, or 150 V CAT IV power circuits
• Power blocking filter not required
• Environmental protection to IP54
• Auto selected output impedance (between 25, 50, 75 and 100 Ω)
• 2 ns pulse for near end fault location
• AUTO option selecting gain and pulse for each range
• Display distance in metres or feet
• Uses five AA (LR6) primary cells

Megger TDR1000/3P Handheld TDR

Technical Specification of Megger TDR1000/3P

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Miller® MA03 Advanced Fiber Optic Preparation Kits

Miller® MA03 Advanced Fiber Optic Preparation Kits

Miller® MA03

Advanced Fiber Optic Preparation Kits

Cable Jointing Tools

Miller Cable Tools are suitable for the Fiber Optics, Electrical, Electronics and Telecommunications industries – tools to strip, core, cut, crimp and slit fiber optic cables to allow splicing and termination of cable.

Ripley Tools is proud to announce the new Miller® MA03 Advanced Fiber Optic Preparation Kits, packed with the latest and most trusted Miller® tools and essential for any fiber cable technician.

The professional-grade, heavy-duty kits are available with either a convenient hands-free tool pouch or a durable molded case with precision cut EVA foam to keep fiber tools organized and protected.

Inside are award-winning, patent-pending Miller® tools, including the ACS+ Slitter for Armored Cable, MB04 FTTX Drop Cable Slitter, and the MSAT® 16 Mid-Span Access Tool with 16 unique cable diameter settings. The preparation kits would not be complete without a pair of precision Miller® fiber strippers, the KS-1 Kevlar® Shears, a compact FTS Buffer Tube Scorer, and a CA Series Cable Grip Tool.

Fibre Optic Cable Splicing, Jointing, Terminating & Stripping Tools

The customized Miller® storage pouch is a must for the professional with its durable 1680D high-density oxford fabric construction for added wear and water resistance.

With 13 dedicated pockets and a large internal space, there’s room to keep all the essential Miller® tools and more. It features an ergonomic carry handle and a removable long adjustable strap that doubles as a shoulder or waist strap for hands-free use. The zippered lid keeps tools protected from debris, and a heavy-duty snap keeps the top open for quick access.

For the technicians that prefer a hard-sided tool case, the new double-walled molded case is a durable and lightweight option. Its EVA foam inserts are cut to fit each of the included Miller® products, protecting the precision tools from damage and saving time looking for tools. Robust, snap-fit latches keep the kit securely closed, and the molded ergonomic handle fits comfortably in either hand.

For decades, Ripley Tools has collaborated with cable manufacturers and professional installers to design and manufacture some of the industry’s most trusted tools under the Miller® brand name.

“Ripley has been a leading provider of custom kits to telecom operator and power utility professionals for decades,” says John Jutila, CEO Ripley Tools. Jutila adds, “With advice from our current customers, we tailored a quality Miller tool assortment and custom-built case to offer to all optical cable technicians at a competitive price as a standardized field kit covering a wide variety of installation applications.”

The Miller® MA03 Advanced Fiber Optic Tool Kits are just two of the many solutions launched by Ripley Labs, the global research development and innovation center at Ripley Tools.

Miller is a Ripley brand – the full product range of high quality LV-HV cable jointing tools and wire preparation for MV-HV Power Cables, Transmission & Distribution, CATV, Electrical and Telecommunications includes Miller, Utility Tool and Cablematic.

THORNE & DERRICK

Thorne & Derrick are national distributors of LV, MV & HV Cable Installation, Jointing, Substation & Electrical Equipment – servicing businesses involved in cabling, jointing, substation, earthing, overhead line and electrical construction at LV, 11kV, 33kV, 66kV and EHV. Supplying a complete range of power cable accessories to support the installation and maintenance of low/medium and high voltage power and fibre cable systems:

• Slip-on Cable Terminations
• Cold-shrink Cable Terminations
• Heat-shrink Cable Terminations
• Cable Joints – Heat & Cold-shrink
• Separable Connectors (Euromold)
• Surge Arresters & Switchgear/Transformer Bushings

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV 

How To Resolve Rising Fault Current Levels On Your Overhead Network

• Special thanks to Jonathan Hopkins (Sales Director) at S&C Electric Company for the kind permission to republish the following article.

S&C Electric Company

S&C Electric Company is a leading provider of switching, protection and control solutions for medium voltage electric power systems. Headquartered in Chicago, S&C is applying its heritage of innovation to address challenges facing the world’s power grids and thus shaping the future of reliable electricity delivery. The mission of S&C is to continually develop new solutions for electricity delivery, fostering the improved efficiency and reliability required for the intelligent grid.

Resolving Fault Current Levels

Are You Experiencing Rising Fault Current Levels On Your Overhead Network?

This could cause miscoordination and existing assets to exceed recommended symmetrical fault ratings. The Fault Tamer, Fuse Limiter from S&C Electric safely addresses this issue by combining the function of a conventional fuse with the benefits of a current limiting fuse.

S&C Electric Fault Tamer Fuse Limiter

S&C Electric Fault Tamer

product FEATURES

Fault Tamer provides many features and benefits above those of traditional fuse cutouts and cutouts used in combination with backup current-limiting fuses.

Improved Transformer Protection

• Ideally suited for protecting single- or three-phase transformers through
  • 100 kVA single-phase at 15 kV
  • 167 kVA single-phase at 25 kV
• Excellent continuous, hot-load pickup, and cold-load pickup capabilities.
• High surge withstand capability. Allows arrester to be mounted on transformer tank without increasing the chance of nuisance operations due to lightning.

Energy Limitation

• Minimizes equipment damage
  • Reduces chances of catastrophic transformer failure from internal high-current faults.
  • Minimizes bushing and tank damage due to external primary faults.
• Improves service continuity
  • Provides complete coordination with upstream lateral fuses.
  • Provides complete coordination with substation instantaneous relay settings.
• Enhances power quality
  • Minimizes voltage dips that can cause sensitive electronic equipment to shut down.

Operational Characteristics

• Dropout action.
• No parts expelled during circuit interruption.
• Complies with Australian Spark Production Standard AS 1033.1-1990. Ideal for installation in areas prone to grass fires.

Handling Characteristics

• Easy to install/remove using extendo stick. No climbing or bucket truck needed to re-fuse . . . unlike conventional backup current-limiting fuses.
• Retrofits into all vintages of S&C Type XS Fuse Cutouts.
• Operable with Loadbuster^®, S&C’s Portable Loadbreak Tool.

Ratings Data

50/60-Hz Ratings
Voltage, kV						Amperes, RMS
System Class, ANSI (IEC)	System Maximum				BIL	Cont.	Interr., Sym.
	60 Hz		50 Hz
	Three- Phase♠	Phase-to-Neutral	Three- Phase♠	Phase-to-Neutral
15 (12)	15	8.7	15	8.7	110	20	12 000
	15	8.7	15	8.7	125
25 (24)	29	16.8	26	15.1	125
	29	16.8	26	15.1	150
	29	16.8	26	15.1	150
22/38 (20.8/36)	–	22	–	20.8	150
♠ Also applies to phase-to-phase applications. Applications involving single-phase transformers connected phase-to-phase, as well as three-phase applications require the use of a Fault Tamer in each lead.

Operation

On low magnitude faults, just the inexpensive fuse cartridge operates — similar to a conventional fuse cutout. Fault Tamer drops open, providing visual indication that it has operated.

On high-magnitude faults, both the fuse cartridge and the backup limiter operate. The fusible element in the limiter melts in multiple locations, creating myriad series arcs that promote an initial rapid increase in arc voltage. The increased arc voltage efficiently limits current to a small fraction of the prospective peak current. Fault current is driven to zero in a controlled fashion, as the fusible element burns back and arc energy is absorbed by the surrounding sand.

Fault Tamer^® Fuse Limiter | Fault Interruption — How It Works

FAULT TAMER FUSE LIMITERS

TIME-CURRENT CHARACTERISTIC (TCC) CURVES

Curve Type	Ampere Ratings	Fuse Type	TCC Number
15kV to 38kV System Voltages
Minimum Melting	3, 5, 7, 10, 15, 20	Fault Tamer	TCC Number 450-8
Total Clearing			TCC Number 450-8-3
S&C Electric Standard Speed (12kV to 22kV System Voltages)
Minimum Melting	1, 2, 3, 5, 7, 10, 15, 20	Fault Tamer	TCC Number 123-8
Total Clearing			TCC Number 123-8-3

 

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Thorne & Derrick

T&D are Specialist Distributors to UK Distribution Network Operators (DNO’s), NERS Registered Service Providers, ICP’s and HV Jointing Contractors of an extensive range of LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt – this includes 11kV/33kV/66kV cable joints, terminations and connectors for both DNO and private network applications.

Contact our UK Power Team for competitive quotations, fast delivery from stock and technical support or training on all LV-HV products.

All international sales enquiries can be serviced and supplied by our Export Power Team.

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV HV 

Cable Scout+ | Easy-fit Cable Rods To Install Cables In A Safe Way

Cable Scout+ Cable Installation System

Cable Scout+

The Hellermann Tyton Cable Scout+ is a professional cable routing tool which enables installers to easily route cables, saving time, even with the most challenging installations and places difficult to access, including:

• in cavities
• through small access holes
• under floor installations
• over suspended ceilings

The Cable Scout+ Cable Installation tools now has an updated design and improved functionality. A remodelled grip allows the cable rods to be easily screwed together – and all components, rods and attachments can be stored in the handy storage and carrying bags. Cable Scout+ is supplied with a range of useful standard accessories. Additional accessories can be purchased separately for pulling cables into commercial and industrial building services applications.

This practical and self-explaining cable installation system facilitates the quick and easy installation of cables over suspended ceilings, behind walls or under floors and many other applications.

Cable Scout+

Cable Scout+ Sets

A variety of different sets are available depending on requirements. The cable rods are manufactured from high quality Glass Reinforced Plastic (GRP), which enables a load carrying capacity of up to 200 kg. Cable Scout+ offers a range of features which allows the installer to illuminate, grip, inspect and retrieve by using a range of accessories.

The Cable Scout+ is supplied in a useful durable bag which contains the rods and accessories all in one place.

Cable Scout+ Handy Set

The Handy Set is made up for fitting in a tool box.

Contents:

• 1 cable rod x 40 cm (white), 2 cable rods x 40 cm (red), 1 cable rod x 40 cm (blue)
• 40 cm white flexi lead
• Domed bullet
• Mini hook and mini eye

Cable Installation Basic Set

The Basic Set is designed to perform basic cable installation.

Contents:

• 10 rods x 1 m (white), 15 cm white flexi lead
• Gender changer, tuff hook and mini eye

Cable Rod Deluxe SeT

The most comprehensive set is the Deluxe set which is designed for carrying out larger installations.

Contents:

• 2 rods x 1 m (white), 6 rods x 1 m (red), 2 rods x 1 m (blue)
• 15 cm white flexi lead, split ring, gender changer
• Tuff hook, mini eye, domed bullet, flat bullet, beam and single magnet