Uploaded June 2026 | Updated September 2026, 1 week ago
IET On-Site Guide - Maximum Demand and Diversity 😂
In this video, we dive into the brand-new 18th Edition Amendment 4 On-Site Guide (the famous "Tangerine book") and head straight to one of the first pages I check when a new edition lands – the Maximum Demand and Diversity tables.
For years, the On-Site Guide has based lighting calculations on a minimum demand of 100W per lighting point, despite 100W incandescent lamps being banned back in 2009. So, has Amendment 4 finally updated this long-standing guidance to reflect the reality of LED lighting?
Join us as we compare the new Amendment 4 guidance against previous editions, look at the history of lighting diversity calculations, and explore what the changes mean for apprentices, electricians, and anyone studying BS 7671.
⚡ In this video:
• Maximum Demand and Diversity explained
• Comparing the 17th Edition and 18th Edition On-Site Guides
• Why the 100W lamp assumption has survived for so long
• The impact of LED lighting on load calculations
• What Amendment 4 has changed
• Where to find more detailed guidance in Guidance Note 1
Whether you're an apprentice learning the trade, preparing for your 18th Edition qualification, or simply interested in the latest changes to BS 7671, this is a small update that could have a big impact on how you approach electrical design calculations.
Have you checked the new On-Site Guide yet? What was the first page you turned to?
== 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 - Maximum demand and diversity
00:23 - 2015 On-Site Guide
00:36 - 100 watt lamps
00:50 - Fluorescent lighting
01:13 - 2022 On-Site Guide
01:48 - Electric heaters
02:06 - Changes in 2026?
02:33 - At last
🔔 Subscribe for more free electrical training videos youtube.com/c/GSHElectrical?sub_confirmation=1
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
You can follow me day by day on Facebook, Instagram, Twitter and TikTok lookout for "GSH Electrical".
▶️ FACEBOOK facebook.com/gshelectrical
▶️ INSTAGRAM instagram.com/p/BrIhZmrAYGDTmjMdb9lUNQodMevqsbDDki3qpQ0
▶️ TWITTER mobile.twitter.com/gsh_electrical
▶️ TikTok vm.tiktok.com/ZMRBLFdhe
#GSHElectrical #Electricaltrainingvideos #BS7671 #18thEdition #Amendment4 #OnSiteGuide #Electrician #ElectricalTraining #ApprenticeElectrician #MaximumDemand #Diversity #LEDLighting
IET On-Site Guide - Maximum Demand and Diversity 😂
In this video, we dive into the brand-new 18th Edition Amendment 4 On-Site Guide (the famous "Tangerine book") and head straight to one of the first pages I check when a new edition lands – the Maximum Demand and Diversity tables.
For years, the On-Site Guide has based lighting calculations on a minimum demand of 100W per lighting point, despite 100W incandescent lamps being banned back in 2009. So, has Amendment 4 finally updated this long-standing guidance to reflect the reality of LED lighting?
Join us as we compare the new Amendment 4 guidance against previous editions, look at the history of lighting diversity calculations, and explore what the changes mean for apprentices, electricians, and anyone studying BS 7671.
⚡ In this video:
• Maximum Demand and Diversity explained
• Comparing the 17th Edition and 18th Edition On-Site Guides
• Why the 100W lamp assumption has survived for so long
• The impact of LED lighting on load calculations
• What Amendment 4 has changed
• Where to find more detailed guidance in Guidance Note 1
Whether you're an apprentice learning the trade, preparing for your 18th Edition qualification, or simply interested in the latest changes to BS 7671, this is a small update that could have a big impact on how you approach electrical design calculations.
Have you checked the new On-Site Guide yet? What was the first page you turned to?
== 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 - Maximum demand and diversity
00:23 - 2015 On-Site Guide
00:36 - 100 watt lamps
00:50 - Fluorescent lighting
01:13 - 2022 On-Site Guide
01:48 - Electric heaters
02:06 - Changes in 2026?
02:33 - At last
🔔 Subscribe for more free electrical training videos youtube.com/c/GSHElectrical?sub_confirmation=1
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
You can follow me day by day on Facebook, Instagram, Twitter and TikTok lookout for "GSH Electrical".
▶️ FACEBOOK facebook.com/gshelectrical
▶️ INSTAGRAM instagram.com/p/BrIhZmrAYGDTmjMdb9lUNQodMevqsbDDki3qpQ0
▶️ TWITTER mobile.twitter.com/gsh_electrical
▶️ TikTok vm.tiktok.com/ZMRBLFdhe
#GSHElectrical #Electricaltrainingvideos #BS7671 #18thEdition #Amendment4 #OnSiteGuide #Electrician #ElectricalTraining #ApprenticeElectrician #MaximumDemand #Diversity #LEDLighting
