Another Hot tub install

[marcuswareham]

I am still thinking of going down the supplementary rod road just incase the loss of a PEN conductor

Would TT not be safer than a rod attached to the PME earth, as with TT there is no risk from open PEN conductor. And for the suplimentery rod to be of any use it would need to be around the 2 ohm mark (depending on the fault) which could be hard to achieve

 

[Gazthesparky]

Would TT not be safer than a rod attached to the PME earth, as with TT there is no risk from open PEN conductor. And for the suplimentery rod to be of any use it would need to be around the 2 ohm mark (depending on the fault) which could be hard to achieve

I get that but it seems silly to go to the effort of isolating the extremely efficient and low resistance PME earth path and solely relying on the fluctuating and higher earth rod path.

I know this is the big debate and can see both sides. If only we had something like a regulations book to give definitive answer lol

Failing that I scrap the rod idea and just use the PME and hope that there is never a PEN Failure.

My gut is telling me that although I need to achieve the 2 ohm mark on the rod to be successful it is better being there and providing some sort of earth path than not being

Im also going to install a DP RCBO so this will disconnect both live conductors should a fault occur.

 

[littlespark]

I never understand this instruction from a hot tub installer.... “leave an isolator and 5m of flex“

so they want you to leave a connected flex, with bare ends, and the only protection is hoping no one turns on the isolator.
even padlocking it and leaving the key in the hands of a normal person (the customer) is questionable.

 

[Gazthesparky]

I never understand this instruction from a hot tub installer.... “leave an isolator and 5m of flex“

so they want you to leave a connected flex, with bare ends, and the only protection is hoping no one turns on the isolator.
even padlocking it and leaving the key in the hands of a normal person (the customer) is questionable.

I know right I am planning to connect the flex up in an adaptable box and leaving the isolator switched off. That way I know the cable is terminated safely. My only concern is the hot tub company not liking it and trying to charge the customer for a return visit as they just want to see a coiled flex ready to go.



This is the paperwork they provided to the customer even there so called example of the supply rough no glands on the isolator the SWA swooping and cable tied to a couple of brackets and the fact that they have left a coil of cable potentially live. this is how they are wanting the install to be left

 

[Mike Johnson]

These are double pole switching: Electrical Wholesaler - Hager RCBO 2P(1P+N) 6kA B-40A 30mA A Class AD940J - https://www.electricalwholesaler.ie/products/switchgearfuses/switchgeardistribution/rcboresidualcurrentbreakers/hagerrcdrccb2p40a30maaclassad940j. All the double pole switching units that are definitely double pole are two module wide, all those that say they are and are only one module wide on investigation are not.

 

[stevethesparks]

These are double pole switching: Electrical Wholesaler - Hager RCBO 2P(1P+N) 6kA B-40A 30mA A Class AD940J - https://www.electricalwholesaler.ie/products/switchgearfuses/switchgeardistribution/rcboresidualcurrentbreakers/hagerrcdrccb2p40a30maaclassad940j. All the double pole switching units that are definitely double pole are two module wide, all those that say they are and are only one module wide on investigation are not.

What about the Wylex NHX miniature rcbo's, it's a switched neutral.

 

[SJD]

Just checked, the Fusebox RCBO are not DP switching so would be unsuitable for a TT style of supply isolation for an open PEN risk.

The older Fusebox RCBOs are not DP, but the new compact ones are DP, for example RTAMB32.

 

[pc1966]

The older Fusebox RCBOs are not DP, but the new compact ones are DP, for example RTAMB32.

I found that later, once the OP linked to the newer model!

 

[Mike Johnson]

I am surprised that Wylex have been able to produce a switched neutral RCBO in a single module, what surprise's me mostly is that if and I emphasise the if they are able to achieve a 3mm air gap (unverified) on both the phase and neutral in that space I would like to see how they do it, because that is what is required under EU specifications.

 

[nicebutdim]

I am surprised that Wylex have been able to produce a switched neutral RCBO in a single module, what surprise's me mostly is that if and I emphasise the if they are able to achieve a 3mm air gap (unverified) on both the phase and neutral in that space I would like to see how they do it, because that is what is required under EU specifications.

Can't find a single module DP RCBO tear down, but here's one of the Crabtree/Wylex single module RCBO/AFDD which crams even more into the same space.

View: https://www.youtube.com/watch?v=gdVntVfP6Q8