TT Systems. Time-delay RCD main switch

by Steve on March 22, 2009

Q Is a time-delayed RCD main switch required in the consumer unit of a new domestic installation supplied by a TT system?   A Provided that the consumer unit is of all insulated construction and all the final circuits are RCD-protected, a time-delayed RCD main switch is not required. How is 0.2s Achieved? A 0.2s [...]

Tagged as: Time-delay RCD main switch, TT Systems

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TT systems. Bonding in bathrooms

by Steve on March 22, 2009

Q Does the dispensation in Regulation 701.415.2 to omit supplementary bonding in a bathroom apply to TT systems?   A Yes it does apply to TT systems. Regulation 701.415.2 states that supplementary bonding may be omitted where: i) All final circuits in that location comply with 0.4 sec disconnection ii) All final circuits in that [...]

Tagged as: Bonding in bathrooms, TT Systems

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TT Systems. Zs reading higher than tabulated

22 March 2009

Q I am measuring a Zs of 140Ω on my final circuits. Table 41.3 gives a maximum of 1.44Ω. I know that a Ze below 200Ω on a TT system is acceptable (Table 41.5 note 2). Is my Zs ok? A Yes it is acceptable. As long as your circuit is protected by an RCD. [...]

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Bonding on sink?

4 May 2009

  Q Do I need to carry out supplementary bonding on a sink? A Probably not. On-Site Guide section 4 states that: Supplementary bonding is required by BS7671 701.415.2 in some locations. (Generally in Special Locations. A kitchen or utility room is not one of these).   However, if the installation meets the requirements for [...]

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Bonding in a Bathroom?

4 May 2009

  Q Do I need to carry out supplementary bonding in a bathroom? A Maybe not. On-Site Guide section 8 states that: Supplementary bonding is required by BS7671 701.415.2 in Special Locations.   However, supplementary bonding may be omitted where all of the following conditions are met: Disconnection time of 0.2 for, TT 0.4 for [...]

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Maximum length allowed for final circuits

6 May 2009

  Q   What is the maximum length allowed for final circuits? A   There are many factors which will affect the maximum allowed length of cable runs for final circuits. Calculations must be made to take into account Type of supply Installation (Reference) Method Ambient Temperature Protective Device Conductor Material Volt Drop   But [...]

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Where to fit fire rated downlights

10 May 2009

Are fire hoods or fire rated down lights required in every situation? Research was commissioned in 1996 to look into the effect on the fire resistance of plasterboard ceilings with conventional rectangular joists having recessed down-lights installed with no boxing or fire hoods. The results were published in the July 1996 edition of Building Control [...]

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Cables concealed in walls at less than 50mm deep

17 May 2009

Q During Periodic Inspections I often find that cables are concealed in walls at less than 50mm deep and are not protected by RCD. Which Recommendation Code should I give?   A Code 4 (does not comply) Although all installations need to be assessed against the current edition of BS7671, this does not necessarily mean [...]

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TT circuits require a disconnection time of 0.2 seconds

22 May 2009

  TT circuits require a disconnection time of 0.2 seconds.  (BS7671 Table 41.1). Q How can this be achieved when the Max Loop Imp Tables in BS7671 only deal with 0.4 and 5 seconds?   A BS7671:2008 The note below Table 41.1 states that: TT disconnection time of 0.2 secs up to 32A & 1 [...]

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Passionate About Lighting

5 June 2009

  Passionate About Lighting   After enquiring about the new Low Energy Lighting options offered by Aurora, Adam and I were invited by director Stephen Hurrell, to visit the Aurora Lighting Showroom at Welwyn Garden City.   Stephen told us that Aurora was started in 2000 by a group of electricians who wanted to offer [...]

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Recessed Downlights

5 June 2009

Recessed Downlights As electrical contractors we regularly install 12 volt recessed downlights and needed to find a reliable and reasonably priced product. We have found that sticking to one familiar core product makes life easier.   When installing recessed downlights the following are essential to us: Knowing the lighting effect created by a particular type [...]

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Principles

4 July 2009

PRINCIPLES Delve into the nuts & bolts of Electricity The History of Electricity Very Basic Electricity Basic Electricity Principles of electricity A simple generator Is Low Voltage Lighting the same as Low Energy?

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Revenue Blitz

9 July 2009

Revenue Blitz Contractors are bracing themselves for another sweeping overhaul of the CIS tax system after the government pledged to stamp out bogus self employment.   Very little detail has emerged about Chancellor Alistair Darling’s plan to attack “false self-employment” but some contractors fear it will pile-up extra costs in employers’ national insurance payments.   [...]

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Can I issue Part P & Installation Certificates for other peoples work?

8 September 2009

  Can I issue Part P & Installation Certificates for other peoples work?   Section 1.28 of Approved Document P does clearly state that a 3rd party may not issue an Installation Certificate.   This may only be issued by the installer responsible for the installation work. A third party could only sign a Periodic [...]

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Big Red Book Review

27 September 2009

  Big Red Book Review    BS 7671:2008 What were your thoughts when you first encountered The Big Red Book?   Our Amazon reviewers made the following observations:   1001 ways to use an RCD A murder mystery where people and livestock are getting murdered all across Europe. Only one man can stop it – [...]

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Disposal of Redundant Lamps

4 October 2009

  Eco Friendly Disposal & Recycling   Why recycle lamps? Recycling specialists Envirogreen say: “Research shows that there are more than 100 million fluorescent and highway lamps used in the United Kingdom each year which produce in excess of 3,100 tonnes of waste material which, until recently, has ended up in landfill sites. Even though [...]

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KVA to Amps to KVA

1 November 2009

Converting from Amps & KVA for AC installations   To Find AC Single-Phase Three-Phase   Amps when Kilowatts are known Kw x 1000 V x pf Kw x 1000 1.73 x V x pf Amps when KVA are known KVA x1000 V KVA x 1000 1.73 x V Kilowatts I x V x pf 1000 [...]

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Power Factor Correction

1 November 2009

    Power Factor Correction Of Linear Loads In the electricity industry, inductors are said to consume reactive power and capacitors are said to supply it, even though the reactive power is actually just moving back and forth on each AC cycle. It is often desirable to adjust the power factor of a system to [...]

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What is an Energy Efficient Light Fitting?

5 November 2009

What is an Energy Efficient Light Fitting?   As far as the Building regulations are concerned an Energy Efficient Light Fitting can only accept lamps with a luminous efficacy exceeding 40 lumens per circuit watt.   Circuit watts include the power consumed by both lamps and control gear including power factor correction equipment.   A [...]

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Electricians and the Building Regulations

8 November 2009

As well as complying with Part P (Electrical) electricians must be aware that they are required to comply with other parts of the Building Regulations.  The Building Regulations are Statutory (Law) and therefore care should be taken to comply with all aspects.   The Scope of Part P of the Building Regulations (England and Wales) The [...]

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Building Regs Part B Fire Safety

15 November 2009

Building Regs  Part B         Fire Safety   Reference to: Building Regs Part B Smoke & heat detectors, wiring & positioning of,  OSG 7.5.2 Emergency Lighting         Also BS7671 Regulation 527 refers to: The Selection and Erection of Wiring Systems to Mimimize the Spread of Fire.     The provision of Fire detection [...]

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Smoke Alarm Sensor Types

13 November 2009

    Types of Smoke Alarm Sensor   The following smoke alarm sensor types are suitable for different applications.   Optical or Photoelectric Sensitive to larger smoke particles produced by smouldering fires like furniture.   Suitable for mounting in landings and hallways to reduce false alarms from kitchens but not in steamy areas near to [...]

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Building Regs Part F

9 November 2009

Building Regs  Part F          Ventilation Adequate ventilation and installation of the correct siting and sizing of extract fans.   Extractor fans are required in rooms where water vapour and pollutants are present to prevent them spreading to other parts of a building. More information on Extract fans & ventilation .   Find related articles at Electricians and [...]

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Ring Main Testing Video

3 February 2010

  Here’s another informative video from electrical guru Christopher Kitcher.  Here Chris shows how to carry out a ring main circuit test. It may take a few minutes for the video to load. Find more instructional videos in the Electrician’s Resources Archive.   Find more info on R1+R2 and Resistance of Copper Conductors. ElectriciansBlog.co.uk

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Electrician’s Mates Looking For Jobs

30 January 2011

Free Listing of Electrician’s Mates Looking For Work. (see comments at bottom of this page) Please Note: There’s also an Electrician’s Apprentices Page If you need a hand and want to give someone an opportunity to prove themselves you’ve arrived at the right place. You can search below for Electrician’s Mates who are looking to find [...]

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Apprentice & Trainee Electricians Looking For Jobs

12 April 2011

Listing of Apprentice Electricians Looking For Jobs. (see comments at bottom of this Page). Please Note: There’s also an Electrician’s Mates Page. If you need a hand and want to give someone an opportunity to prove themselves you’ve arrived at the right place. You can search below for electrical apprentices who are looking to find work in your area. [...]

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Terra 51 Electric Vehicle EV Rapid Charging Station

1 February 2012

The changeover to electric vehicles is long overdue, especially with the inevitable upward trend in petrol and diesel prices. Electric cars and vans will soon be commonplace and many manufactures are due to roll out their electric vehicle offerings this year. Let’s hope that the installation and maintenance of Electric Vehicle or EV charging stations will soon be a [...]

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Smart Meters- Intelligent metering systems

29 January 2012

Smart Meters are due to be installed in most UK homes. Will this be all good news for consumers?  Will it create work for electricians? Are Smart Meters a Good Idea? Under European Directives, all member states are required to install ‘intelligent metering systems’ – smart meters – to at least 80% of domestic electricity [...]

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Electricians Fighting To Keep JIB Agreement

21 January 2012

This article highlights some main points of the recent dispute over electrician’s pay and working conditions. Decisions that are made now between the unions will affect electricians for years to come. I got the email below from David W and wanted to pass on his sentiments. I’ve also included some background info on the dispute [...]

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Central Heating Boiler Wiring Connections

19 January 2012

This article may prove useful to electricians when connecting a boiler to a new or existing central heating system with pump over-run. The diagrams show some of the most commonly found domestic boiler control panel wiring connections. Electrical Connections to Boilers Only competent and trained persons such as qualified electricians, plumbers and gas fitters should attempt to [...]

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Electrical Installation Condition Report- EICR Training Video by Learning Lounge

18 December 2011

This Learning Lounge Electrical training video gives a great overview of the Electrical Installation Condition Report EICR introduced in Amendment 1 of BS7671. If you’ve had a chance to watch it I would be interested in your comments. You can subscribe to Learning Lounge Electrical to watch this video now!  See info at bottom of this page. [...]

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Voltage Optimisation- VPhase Training Video

4 December 2011

If you’ve ever wondered about domestic voltage optimisation, how it works and how it is installed, then you can find out here. VPhase are the market leading domestic voltage optimization company, whose product is proven to save up to 12% of home electric bills. They offer free training seminars throughout the UK to demonstrate their products [...]

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UK Electricians Jobs- Renewables and Energy Saving Work for Electrical Contractors

2 December 2011

The ECA has urged electricians across the country to ‘Gear Up’ and obtain the additional ‘know how’ they need to install and maintain ‘low to no carbon’ energy solutions. The renewables and energy sector is set to become a major source of jobs for electrical contractors. Electricians are at the forefront of the Eco Renewables [...]

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Electrical Installation Condition Report- EICR advice from Elecsa

2 December 2011

ELECSA, one of the UK’s leading competent person schemes run by electricians for electricians, is urging contractors not to be concerned by rumours in the industry on the new reports and coding. Under the existing arrangements for Periodic Inspection Reports (PIRs) a numbering system of one to four indicates the seriousness of any departures.  Now [...]

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