Discuss Tt System Fuseboard For 17th Edition in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

B

bluecallum

Hi,hoping Someone Can Help,going By 17th Edition,what Sort Of Consumer Unit Is Now Required When Doing A Tt System,as The New Boards Now Have 2x30ma Rcd's.thanks
 
In theory you don't need a 100ma RCD as a main switch, but there's no harm in it as long as you don't leave in the old voltage operated one :-O In theory one of the 30ma RCDs of the consumer unit would trip before a 100ma main switch but at least if someone accidentally touched the live tails it would still trip :-D Have a read of Reg 411.5 The trip rating of the RCD now depends on the resistance of earth fault path through the earth electrode, the 17th Edition regs don't specify a specific tripping current although you could install a 300ma RCD as a main switch between the supply tails and the Consumer unit and tell the customer it is there for Fire Protection. Reg 532.1.
 
Are You Saying That You Can Use The New 17th Edition Board With The Two Manufactured Rcds
 
Hi just been having a read around regarding tt installations, I want to repleace my old mk 100ma rcd main switch for a up to date one. My Zs is reading 270 ohms, not too far away from the board so I'm guessing the Ra is still going to be a lot higher than 200 ohms. So whats the deal..? Do I need to get the Ra below 200ohms by installing a new earth rod or like it say above from Shakey will my new dual 30Ma rcd board be satisfactory ?
When does the below 200 ohms appay and when does the 1996 ohms apply...?
 

Reply to Tt System Fuseboard For 17th Edition in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock