Supplementary bonding in a TT installation

[lilman]

Good evening all.

I understand that supplementary bonding can be omitted in a room containing a bath or shower if certain conditions are met - however the first of these conditions is that the circuits in the special loction have to comply with the requirements for automatic disconnection (411.3.2). Am I right in thinking that as a TT install could rarely meet this requirement (RCDs have to be used), then all TT installs would need supplementary bonding? Am I right or am I confused? Please help me. Thanks

 

[M107]

On a TT system you should have;

(1) 30mA rcd on the tails pre cu (on older installs)

(2) 30mA rcd as cu main switch (on older installs)

(3) cu with 100mA s type rcd main switch + 30mA rcd on split side (16th compliant)

(4) DP mainswitch with dual 30mA rcd cu (17th compliant cu)

& supplimentary bonding is required in all cases, but as you say can be ommitted as per number (4) if certain requirements are met.

 

[steptoe]

it all depends if you are going to mechanically protect your cables or not, or if they can meet the 50mm deep rule.

if so then you can choose to protect your install with a 100mA RCD with supplementary bonding and off course the obligatory 30mA socket for outdoor use.

more info required as this can be a minefield .

HTH,

Albert

 

[steptoe]

On a TT system you should have;(1) 30mA rcd on the tails pre cu (on older installs)was never required

(2) 30mA rcd as cu main switch (on older installs)was never required

(3) cu with 100mA s type rcd main switch + 30mA rcd on split side (16th compliant)was never required in 16th, 30mA protection only required for socket outlets likely to be used outside the EZ

(4) DP mainswitch with dual 30mA rcd cu (17th compliant cu)not required if using other means of protection

& supplimentary bonding is required in all cases, but as you say can be ommitted as per number (4) if certain requirements are met.may be totally omitted in most cases depending on using RCDs for supplementaru protection (ie X5 test)

me red

 

[The Godfather]

701.415.2

Don

 

[NozSpark]

I just had my inspection (TT install) and there was no supplementary bonding in the bathroom.... all circuits were 30mA protected (twin RCD CU)

 

[The Godfather]

I just had my inspection (TT install) and there was no supplementary bonding in the bathroom.... all circuits were 30mA protected (twin RCD CU)

Main bonding in place?

The Godfather

 

[steptoe]

I just had my inspection (TT install) and there was no supplementary bonding in the bathroom.... all circuits were 30mA protected (twin RCD CU)

as I said, may be totally omitted, your RCD on X5 test is regarded as supplementary protection, as was in using X5 30mA RCD protection for equipment outside the equipotential zone in 16th.

 

[NozSpark]

Main bonding in place?The Godfather

Main earth and PEB (water only - no other services) - both 10mmBlushingBlushing

I know 10mm is not needed to the rod, but I couldn't be bothered getting 2 different lots.......................

:coat :coat

 

[seajayess]

As far as I understand supplementary bonding can be omitted if the three conditions are met.

1 RCD protection for circuits special location / should be in place as TT system

2 Equipotential bonding in place and all extraneous parts in bathroom are connected.

3 Disconnection times can be met, which if RCD protected they should do

Stand to be corrected CJS

 

[kme]

Not by me, you won`t be mate. Concise, easy to read post.

KME

 

[steptoe]

As far as I understand supplementary bonding can be omitted if the three conditions are met.1 RCD protection for circuits special location / should be in place as TT system

2 Equipotential bonding in place and all extraneous parts in bathroom are connected.

3 Disconnection times can be met, which if RCD protected they should do

Stand to be corrected CJS

why cant I write nice simple straight forward explainations like that?

spot on CJS.

 

[Doug]

The 17th edition guidance on the Electrical Safety Council's website includes the following Q & A:

Does the dispensation in Regulation 701.415.2 to omit supplementary bonding in a location containing a bath or shower apply to TT systems?Yes

http://www.esc.org.uk/forum/forum_nd_thread.html