Blog Sparks Direct
Posts Tagged the 17th edition
What is IP Zoning? Update on the IP rating and IP zoning: zone 0, zone 1, and zone 2 only!
We owe our visitors and customers an apology – the recent regulations have modified the “IP rating in the bathrooms – bathroom IP zoning” and the “IP zoning in the bathrooms – IP rating“. It is a simple change – the renouncing / eliminating of the zone three, since it is irrelevant when it comes to light fittings and other electrical devices in the bathroom or shower. Zone 3 has been removed under the 17th Edition Wiring Regulations BS7671. To illustrate the IP zoning regulations there’s the classical bathroom area divided up into areas or “ZONES” which are classified using the numbers 0, 1, and 2(no longer a zone 3). The luminaires are assigned an “IP RATING“(which can be seen in the description of the light fittings on our website) which indicates how much protection they provide against ingress of water and other particles. Each zone has a minimum IP requirement that must be met if a fitting is to be installed in this area. The source for this picture and details: the Aurora Lighting Information on the IP Zoning in the Bathrooms.
IP Zoning in the Bathrooms – the IP Rating and Zones
- IP Zoning – Zone 0 – Inside the bath or shower. Any fittings used here must be SELV (max. 12V) and have a minimum rating of IPX7 (protected against immersion in water). If there’s the likelihood of water jets being used for cleaning purposes, a minimum of IPX5 is required for the light fittings or electrical devices.
- IP Zoning – Zone 1 – Above the bath or shower to a height of 2.25m. A minimum rating of IPX4 is required. If there’s the likelihood of water jets being used for cleaning purposes, a minimum of IPX5 is required for the light fittings or electrical devices.
- IP Zoning – Zone 2 – This is the area stretching to 0.6m outside the bath or shower and above the bath or shower if over 2.25m. An IP rating of at least IPX4 is required. The same as in zone 1 – If there’s the likelihood of water jets being used for cleaning purposes, a minimum of IPX5 is required for the light fittings or electrical devices.
- IP Zoning – Anywhere outside zones 0, 1, and 2 – this is where water jets are not to be used for cleaning purposes, the general rules of BS7671 apply. IP not essential – IP rating is not required.
In zones 1 and 2, SELV or 240V luminaires may be used(remember to respect the IP rating required). As for the final circuits, they all require 30mA RCD protection.
Please Note: The above information is intended as a guide only – if you want to find out more detailed information on the IP rating and the IP Zoning in the Bathrooms, please refer to the IEE Wiring Regulations(BS 7671:2001 section 601).
Hager Distribution Boards, the new Invicta 3 Type B distribution boards – features and benefits(1)
Posted by sparksdirect in all-time best-seller, ask Mr Sparks, consumer units, electrical products, electrical safety tips, guest expert, new technologies, technical data, website update on February 16, 2011
Hager have developed the new Invicta 3 type B distribution board as a solution for modern commercial installations. The Invicta 3 range includes both 125A and 250A boards with multiple incomer choices. The Hager IP65 TP&N distribution boards are suitable for three phase applications where a high IP rating is required. The whole nature of electrical sub and final distribution for commercial installations has changed in the last few years. Typically there is a demand for more outgoing ways, more RCD protection, more metering and more control devices. Electrical distribution is at the heart of a buildings services. Modern distribution boards must enable designs that meet the demands of the 17th Edition, the need for more metering and the demands for energy efficient solutions through control devices or building management systems. This article is the first part of the Invicta 3 Type B Distribution Boards from Hager(read it online) – Features and Benefits, introducing the Top Tap Off, the Shrouded Neutral Bar, the Trunking Entry, and the Clear Labelling.
Hager Invicta 3 Type B Distribution Boards – The Top Tap Off
Hager Invicta 3 Type B Distribution Boards - The Top Tap Off; 100A top tap off allows for board extensions or MCBs up to 100A with a connection kit.
Hager Invicta 3 Type B Distribution Boards – The Shrouded Neutral Bar
Hager Invicta 3 Type B Distribution Boards - The Shrouded Neutral Bar; Clear shrouded neutral bar to IP2X allows the contractor to install cables without removing the shroud. This ensures safe and easy installation.
Hager Invicta 3 Type B Distribution Boards – The Trunking Entry
Hager Invicta 3 Type B Distribution Boards - The Trunking Entry; The unique trunking entry obround system, top and bottom, enables a quick fitting to trunking and without the extra cost in time and materials.
Hager Invicta 3 Type B Distribution Boards – The Clear Labelling
Hager Invicta 3 Type B Distribution Boards - The Clear Labelling; L1, L2, L3 on the moulding are visible with and without the front cover fitted, which show through the cover for ease of line identification.
Make sure you read also the second part of this series – features and benefits of the Hager Invicta 3 Type B Distribution Boards(part 2) – introducing the Single Pole Blank, the Metering, the Aesthetics, and the Choice, or consult the entire range via the Hager website – Hager Distribution Boards. You can buy online the Invicta 3 range of Type B Distribution Boards via SparksDirect at the Industrial and Commercial Consumer Units section. Read more about this range of consumer units via:
- Meeting the 17th Edition needs: the Hager Type B Distribution Boards, Invicta 3;
- 4 more reasons to choose the Invicta 3 Type B Distribution Boards from Hager;
- The Invicta 3 Distribution Boards from Hager: The New Design and Features;
- More features and benefits of Invicta Distribution Boards(Hager Invicta 3 Type N);
The bare bones of protection, the Skeleton Units and their more modern replacements
Posted by the electrician in ask Mr Sparks, consumer units, customer service, electrical products, electrical safety tips, guest expert, new technologies, standards and regulations, technical data on January 18, 2011
The following is a full quote of the article Electrical Wholesaler News posted not long ago via, The bare bones of protection, in which someone at MK Electric talks about the difficulties and hardships of using and working with an old-style Skeleton unit. Of course, these days you can use the 17th Edition Consumer units(see the Complete guide to the 17th Edition Consumer Unit and the Wiring Regulations), but many of the homes and buildings today still use the old-style Skeleton Units.
Joanne Reynolds, Senior Marketing Communications Manager of MK Electric looks at the proliferation of Skeleton Units in older public sector housing and how modern replacements take the pain out of dealing with these awkward systems.
As many will hopefully be aware, many local authorities historically (and almost notoriously) favoured Skeleton Units as the main framework for consumer protection within dwellings. They were never much liked by contractors as they can be awkward to work with and can result in some eccentric arrangements – these were particularly popular in the 1960s through to the 1980s. Indeed, it may now seem controversial that an RCD was favoured as the mains rather than circuit isolator.
Reduce hazards
Sometimes referred to as skeleton boards, these are spine backplate assemblies designed to fit within a Mantel or Clifton type enclosure which is essentially a kind of metal utilities cupboard which may also contain the meter. The Institute of Engineering & Technology (IET) who is responsible for the Wiring Regulations never really liked them either, and the 16th Edition of the regulations implicitly concerned itself with their use and paved the way for the introduction of split load boards. This helped obviate hazards arising in fault conditions, such as the RCD tripping as a result of a downstairs lamp blowing and plunging an entire household into darkness.
As an aside, power supply companies, especially in more rural areas, still manage this; and some argue that there’s little point in protecting against an internal fault when the same external one can still arise. Of course, installers working with older social housing still encounter these and experience difficulties in bringing a property up to current electrical safety standards.
Consequently, while the concept of Skeleton Units is effectively obsolete for new installations, most manufacturers still offer them for replacement purposes. This is because the applications and/or locations can make it extremely difficult to substitute them with a current consumer unit – either for reasons of space, or the ability/inability to provide sufficient circuits. Happily, the modern equivalents take much of the fuss out of dealing with them away, and provide a far faster, cleaner and easier installation than would previously have been the case.
Make improvements
Needless to say, 17th Edition regulations apply as one might expect; and this pressure has combined with the Government’s Decent Homes Initiative targets to make the replacement of these old-style installations imperative. So a great opportunity exists to improve the electrical safety of such properties through up-to-the-minute units; but also to improve the overall quality of housing stock which is conceivably one of the country’s greatest built assets.
Necessarily, high quality proprietorial products are available to make this possible, all of which might be explained by the phrase ‘get the right busbar and you can make any combination of split load’. From the stockist’s perspective, you will never shift millions of these, but they definitely have their market opportunity and the cost and space implications of having a few to hand are negligible. So when an installer needs, and has to have one, because there’s nothing really else that will do, you will have the right product on your
shelves to satisfy his requirement.Features
As mentioned above, there are a number or proprietorial equivalents out there but when seeking to satisfy the particular needs of the installer and end-user alike, there are a number of features that really ought to be incorporated. Look for a DIN rail that is easily removable, as this improves first fix (although remember that if any unused ways are required, a DIN rail mounted blanking plate must be used to complete the installation). Backed out and captive combi-head screws also make for a quicker and easier installation; while modern versions should, against the cramped styles of old, offer far better wiring space to, among other things, allow provision for RCBOs.
Flexibility
Importantly, flexible neutral bar configurations and a floating busbar system (one that can be cut according to the number of devices fitted) are very useful to enable a wide combination of protected and unprotected circuits as well as offer configuration flexibility depending on local authority requirements (be it single/dual RCD/all RCBOs).
If truth be told, no-one really liked dealing with the older-style Skeleton Units if they can help it and it may be thought annoying that they got such a grip in the public sector when they did. That said, they are a frequently encountered reality, and when a Skeleton Unit is all that can replace a Skeleton Unit then at least up-to-date versions now exist that can take much of the pain (and swearing) out of their installation.
Hager Guide to Commercial Installations(5) – building regulations and the Invicta Type B Boards
Posted by sparksdirect in ask Mr Sparks, consumer units, electrical products, electrical safety tips, guest expert, new technologies, standards and regulations, technical data on December 10, 2010
This is the last part(part 5) of the Hager Guide to the Commercial Installations(read more about the Type B Distribution Boards and compliance with standards, the cable entry + the isolation and switching, Protection against fault current, use skilled persons!, and Protection against electric shock and overvoltage), dealing with: the Building regulations, Saving energy, The Invicta Type B distribution boards, and a final question: Why specify Invicta Type B boards? Read / download the complete Hager Commercial Installations guide as a pdf online.
The Hager Commercial Installations and the Building regulations
The Approved Documents L2A and L2B provide guidance to the technical requirements of the Building Regulations in respect to the conservation of fuel and power. While they only affect England and Wales, the principle is still useful for the rest of the UK. Part of these approved documents is to provide the owner with relevant energy meters so that at least 90% of the annual energy consumption can be traced to end use categories – such as heating, lighting or power. To help achieve this, you should install an incoming meter for every building that has a floor area greater than 500m2. In addition, CIBSE TM 39 recommends sub meters should be provided for a final electrical distribution board that has an input power greater than 50kW.
In order to segregate the energy used by different services, such as lighting and power, you can either use two boards which each have separate meters or you might consider using a lighting and power metered board.
Saving energy and the Hager Distribution Boards
Conservation of power cannot just be about measurement. It is also about using efficient systems and controls. Timers and photocells help ensure that energy is used efficiently. More sophisticated control such as knx/tebis bus based systems also offer solutions. Such controls are often DIN rail mounted so provision of extension boxes provides a neat and functional purpose.
The Invicta Type B distribution boards
Hager has developed its new Invicta Type B boards as a solution for modern commercial installations. Electrical distribution is at the heart of a building’s services. Modern distribution systems must enable designs that meet the demands of the 17th Edition, the need for more metering and the demands for energy efficient solutions through control devices or building management systems. The new Invicta range of Type B boards makes it easier for you to design and install electrical distribution systems that meet the needs of today and the future.
Why specify Invicta Type B boards?
- Multiple incomer choices for the 125A boards and the 250A boards Unique trunking entry system – no need for paxolin;
- Earth and neutral bars positioned for easier cabling Transparent IP2X shrouds for earth and neutral bars;
- Optimal cabling space;
- Metering fitted next to incomer within board;
- Wide range of extension boxes for side, top and bottom;
- No spacers needed to mount boards, cableways or extension boxes;
- Removable door and front cover for ease of fitting;
- 125A tap off for board extensions or MCB;
- The Invicta 3 range of Distribution Boards from Hager meeting the 17th Edition regulations;
- Four more reasons for choosing the Invicta 3 range of Distribution Boards;
- More details about the existing 125A and 250A Invicta 3 models.
This is the last part of the Hager Full Guide to the Commercial Installations – read the previous articles about
- the Type B Distribution Boards and compliance with standards(part1),
- the cable entry + the isolation and switching(part 2),
- Protection against fault current, use skilled persons!(part 3),
- Protection against electric shock and overvoltage(part 4)
- Download the full pdf file of the guide via the Hager website.
Hager Guide to Commercial Installations(4) – Protection against electric shock and overvoltage
Posted by sparksdirect in ask Mr Sparks, consumer units, customer service, electrical safety tips, guest expert, standards and regulations, technical data on December 10, 2010
This is part four of the Hager Guide to the Commercial Installations(read more about the Type B Distribution Boards and compliance with standards, the cable entry + the isolation and switching, and Protection against fault current, use skilled persons!), dealing with: Protection against Electric Shock, the Socket Outlets, the Nuisance Tripping, Cables in walls, Protection against overvoltage, and Fire Detection and Alarm Circuits. Read / download the complete Hager Commercial Installations guide as a pdf online.
Hager Commercial Installations – Protection against electric shock
Protection against electric shock needs to be provided by offering both basic protection and fault protection. Basic protection includes the insulation of live parts and barriers or enclosures such as distribution boards. Appropriate devices or blanks must be fitted to maintain IP2X or IPXXB. If the top of the horizontal surface is readily accessible then the level of protection there should be IP4X or IPXXD. Automatic disconnection of supply will usually provide fault protection. This involves protective earthing, protective equipotential bonding and the automatic disconnection of a device if there is an earth fault. The designer will normally need to ensure co-ordination of protective devices and earth fault loop impedances so that disconnection will occur within the maximum times given in 411.3.2.2, 411.3.2.3 or 411.3.2.4.
An additional requirement for the protection against electric shock is to specify RCDs where they are needed. 415.1.1 recognises that RCDs with a rated residual operating current up to 30mA and an operating time not exceeding 40ms at a residual current of 5 provides additional protection for ac systems if the basic or fault protection fails, or against carelessness by the end user.
Hager Commercial Installations – Socket outlets
Regulation 411.3.3 requires that an RCD not exceeding 30mA be provided for:
- Socket outlets up to 20A that are for general use by ‘ordinary persons’.
- Mobile equipment up to 32A that is for use outdoors.
One exception is permitted where the use of the socket outlet is under the supervision of someone ‘skilled’ or ‘instructed’. So, for commercial or industrial applications the designer will need to consult with the client about whether someone who is ‘skilled’ or ‘instructed’ will normally supervise the installation before deciding which socket outlets need RCD protection. Another exception is for a specific labeled/identified socket-outlet for a particular item of equipment.
Clearly ‘ordinary persons’ will use some commercial installations i.e. ‘persons who do not have the necessary knowledge to avoid the dangers from electricity.’ If this is the case then the designer/installer may decide to provide RCD protection to all socket outlets. For socket outlets used by cleaners, those in common or circulation areas, in self-catering areas or which might supply outdoor equipment, it is generally considered that RCD protection is required.
Nuisance tripping with the Hager Distribution Boards
In a commercial installation it is likely that socket outlets will supply computers, printers, copiers and other electronic equipment. This type of equipment produces small amounts of protective current. Nuisance tripping could be a problem if several of these are on one circuit protected by a 30mA RCD. The designer will need to consider this problem and may decide to reduce the number of sockets on each circuit by, for example, increasing the number of final circuits. Alternatively you can label sockets used for such equipment. This, plus the occupant/employer operational systems and health and safety policy, should ensure compliance where RCD protection is not provided.
Hager Distribution Boards – Cables in walls
It is likely that metal partitions will separate rooms in a commercial installation. If this wall has a cable inside it then the requirements of 522.6.8 will need to be met. These requirements are similar to those for socket outlets in that if there is adequate supervision by ‘skilled’ or ‘instructed’ persons then you do not need to provide additional RCD protection. If there is some doubt about this, then the designer could make the decision to apply part (v) of this regulation and provide 30mA RCD protection. This applies to all circuits, not just socket outlet circuits.
Hager Distribution Boards Electric shock protection – conclusion
More circuits need RCD protection since the introduction of the 17th Edition. In commercial distribution boards, it would be appropriate to use RCBOs for individual outgoing circuits.
Remember: In commercial distribution boards it would be appropriate to use RCBOs for individual outgoing circuits.
Protection against overvoltage
Section 443 of BS 7671 deals with the protection of electrical installations against transient overvoltages. These can be from the supply distribution system or generated by equipment. Overvoltage protection by surge protection devices (SPDs) is not generally needed for a distribution board where a suitable rated impulse withstand voltage is declared by the manufacturer. Table 44.4 in BS 7671 provides examples of various impulse categories for equipment and table 44.3 gives the corresponding minimum impulse withstand voltage. For distribution boards where the nominal voltage of the installation is 230/240V or 277/480V category III, 4kV would be appropriate. The designer or installer may choose to apply the requirements of regulation 443.2.4. This uses a risk assessment method to determine whether SPDs are required.
Fire detection and alarm circuits
Chapter 56 of BS 7671 covers fire detection and alarm circuits. Regulation 560.7.1 states that these safety services must be independent of other circuits.
This is also a requirement of BS 5859 Fire Detection and Fire Alarm Systems for Buildings. Clause 25.2 states that the mains supply to the fire alarm system should be from the load side of the main isolating device for the building and have its own isolating protective device (such as a circuit-breaker). The circuit should also be from a point in the electrical distribution system that is close to the main isolating device for the building. In addition, every protective device that can isolate the supply to the fire alarm system, other than the main isolator for the building, should be clearly labeled: “FIRE ALARM. DO NOT SWITCH OFF” in a durable and fade resistant material.
This is part 4 of the Hager Full Guide to the Commercial Installations – read the previous articles about the Type B Distribution Boards and compliance with standards, the cable entry + the isolation and switching, Protection against fault current, use skilled persons!(download the full pdf file of the guide via the Hager website) – we will continue to post the next parts of the guide, keep an eye on Blog SparksDirect].