Electrical Safety in the Home and Garden - Using an RCD and Other Tips to Prevent Shock

Updated on May 1, 2018
eugbug profile image

Eugene is a qualified control/instrumentation engineer Bsc (Eng) and has worked as a developer of electronics & software for SCADA systems.

GFCI or RCD (Residual Current Device)
GFCI or RCD (Residual Current Device) | Source

Be Safe When Using Electrical Equipment Outdoors!

Many of us routinely use electric power tools in the yard and garden for construction and maintenance, typically power drills, saws, hedge trimmers and strimmers (string trimmers). However there's a constant danger of cutting the cord, or the tool getting wet during a rain shower. Or you could drop it into water. Any of these scenarios can potentially result in shock. An RCD (also called a GFCI) safely shuts off power when this happens.

If you would like to ask me any questions, please leave a comment at the bottom of the article.

What Does an RCD Do?

An RCD or "Residual Current Device", shuts off power when there's an electrical "leak", increasing your safety. An RCD is an electrical safety device which can typically be plugged into a standard socket outlet.
An RCD is also known as a GFI (Ground Fault Interrupter) or GFCI (Ground Fault Circuit Interrupter) in the US and some other countries. Historically these devices were called ELCBs (Earth Leakage Circuit Breakers).

What is Meant by "Ground" or "Earth" ?

If you've ever opened a plug attached to the flex of an appliance, you'll notice that there is a green or green/yellow wire atached to one of the pins. If the appliance has a metal body, this wire is attached to the casing via the power cord. If any of the live components inside the appliance come loose or break, and touch the casing, this wire draws a surge of current and may blow the fuse (if fitted in the plug). The miniature circuit breaker (MCB) at the consumer unit (or "fusebox") may also blow. However the RCD at the consumer unit will almost certainly trip. Any of these scenarios will safely cut off power.

"Ground" and "earth" mean the same thing. The term "ground" however is used in the US. For a more detailed discussion, see my article What Is the Ground (Earth) Wire For?

How Does an RCD Work?

Normally current flows out of a socket outlet to an appliance via the live (known as "hot" in the US) conductor in the power cord, then returns back to the socket via the neutral conductor. An RCD monitors this current, and both the current through the live and neutral conductors should be equal. If a live to ground fault occurs, some of the current doesn't return, and instead takes a "detour" to ground. The RCD detects the imbalance of currents and shuts off power in less than 30 milliseconds.

What Type of Faults Will Shut Off an RCD?

Typical live to ground faults are:

  • Someone touching the live conductor in a damaged flex. Current flows through their body to ground. In this scenario, an RCD may or may not shut off power (it depends on the current which flows) and the person will still experience a shock. However if the current exceeds 30ma, the RCD will trip, hopefully preventing electrocution.
  • You cut through the cable of a hedge cutter, current flows to ground via the blade. This is rare nowadays since most power tools and garden tools are double insulated with plastic casings and no ground (earth) conductor in the flex.
  • The socket outlet on an extension lead gets wet when left on grass or in a puddle.
  • A fault occurs inside an appliance causing wires or other live metal parts to touch the internal grounded body of the appliance.
  • Indoors, the connector at the end of the flex of a kettle is left in water on a sink while plugged in.

What Type of RCD Should I Choose?

RCDs are sometimes fitted as an integrated moulded plug on an extension lead. You can also buy an adapter which you plug into a socket outlet. You then plug the extension lead or appliance into the adapter. Another alternative is to replace the socket outlet you use for powering outdoor equipment with a version which has integrated RCD protection. Yet another option is an RCD "plug". This can be wired to the power cord of an appliance as a replacement for the standard plug.

If you use an RCD adaptor, remember you are protected "downstream" of the adaptor. So ideally it should be plugged into a socket and if an extension lead is used, this is then plugged into the adaptor. If you plug the adaptor into a socket at the end of the extension lead, the adaptor won't give any protection if for instance you cut through the insulation of the extension lead and expose a live conductor.

Hang On, Don't I Have an RCD Fitted at My Electrical Panel!?

Most modern electrical installations have RCDs installed as standard at the electrical panel or "fusebox" and this protects socket outlets. However older homes may not have one of these devices. If you don't, it's worth considering an upgrade by a qualified electrician. Even if you do have an RCD at the panel, it's no harm using an RCD adapter on your extension lead as added insurance when working outdoors, just in case the primary device fails. Both the RCD at the fusebox and RCD adapters have test buttons. These should be pressed regularly to ensure they are working properly (just like the way you press the button on your smoke alarm to test it)

If you do work in other people's homes and use power tools or other electrical equipment in damp conditions, you don't know whether their electrical installation is safe and up to scratch, so it's a good idea to have one of these fitted to your extension cable.

A DIN rail mounted modular RCD like this one is fitted as standard at the electrical panel
A DIN rail mounted modular RCD like this one is fitted as standard at the electrical panel | Source

Warning !!!

Remember an RCD isn't guaranteed to save your life in the event of an electrical leak. However it does lessen the risk of getting a severe electrical shock or even being electrocuted. You still need to take sensible precautions when using electrical equipment outdoors.

How to Prevent Electric Shock

  • Don't use electrical devices outdoors in wet conditions
  • Don't wear leather soled shoes
  • Make sure the insulation of power cords is undamaged with no exposed conductors
  • Be conscious at all times where the power flex is so that it can't get cut by the tool. Many tools are now fitted with brightly coloured power cords which are easily seen. However If the cord is black or dark coloured, you can easily lose "visual contact" with it in low light conditions, especially when it's covered with an accumulation of foliage

Garden equipment can be corded and powered by mains electricity.
Garden equipment can be corded and powered by mains electricity. | Source
Don't tape up damaged flexes.
Don't tape up damaged flexes. | Source

Questions & Answers

    © 2016 Eugene Brennan

    Comments

      0 of 8192 characters used
      Post Comment

      • Larry Rankin profile image

        Larry Rankin 

        2 years ago from Oklahoma

        Important safety tips.

      working

      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, dengarden.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://dengarden.com/privacy-policy#gdpr

      Show Details
      Necessary
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
      Features
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Marketing
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Statistics
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)