Hot tub installation !

[devonsparky]

This is a follow up to a thread I started yesterday.

I have been working all day installing a hot tub situated outside on a patio slabbed deck.

Contrary to what I was told, it was TN-C-S supply so here is how I have wired it.

• From Henly blocks - 25mm tails to a one way board (Main Sw RCCB - 50A MCB)

• 10mm 3 core SWA from board to 63A rotary isolator and from rotary isolator to hot tub

• Earth rod with 10mm G/Y back to one way board and then used one core as an earth to the hot tub and connected the armour to the earth bar too.

Time beat me today so I have not connected into the Henly blocks yet and tested .......................... Is this how you guys would have done it. 10 years in the game and an approved electrician and it's still nice to get feedback off of this forum !! ha ha

 

[electric will]

I'm sticking with tt then, trouble is there's pros and cons for either.

 

[devonsparky]

Me too 'Will' ............. and I'm going to smash up my laptop so I can't read any more messages to alter my thinking anymore !!!!

 

[SPARTYKUS]

Rcd is statistically more (much more) likely to fail than loosing the PEN.

Now I am being devils advocate!

 

[electric will]

Maybe the you should have a 100ma at main board and a 30ma at the tub Why not just drag the hot tub into the lounge?

 

[mayfair]

Your some bloody comfort

Rcd is statistically more (much more) likely to fail than loosing the PEN.

Now I am being devils advocate!

 

[Engineer54]

last hot tub i did was off TNS , didnt bother with any rods :-D

If the hot tub was located on bare ground or grass, i think i'd be also installing a rod, even if it was a TN-S supplied installation. Your still going to get a potential difference between true earth and the DNO TN-S earth.....

As for the Regs, i think they state somewhere, that a TNC-S supply can be used, for supplying hot-tubs and the like provided an earth electrode of a certain value is also provided.... I think that value was around 20 ohms, but i wouldn't swear to it...

 

[electric will]

Oh don't start this thread again! I've made up my mind with these tt all the way

 

[SPARTYKUS]

How many lost neutrals have you seen? And how long before fixed.

Me-none.

Knackered RCDs owner unaware of, prob been like it since installation by a (*cough*) electrician?

Me-about 15.

 

[Engineer54]

Oh don't start this thread again! I've made up my mind with these tt all the way

I'd probably agree with you too, especially if the Tub was located/positioned on bare ground or grass, but not with anywhere near a 200 ohm Ra value... lol!!

 

[SPARTYKUS]

I think earlier posters were trying to decide on TNCS or TT. E54 you're proposing TNCS with a back up rod as well aren't you. All connected together, so to speak.

 

[Chr!s]

If the hot tub was located on bare ground or grass, i think i'd be also installing a rod, even if it was a TN-S supplied installation. Your still going to get a potential difference between true earth and the DNO TN-S earth.....


As for the Regs, i think they state somewhere, that a TNC-S supply can be used, for supplying hot-tubs and the like provided an earth electrode of a certain value is also provided.... I think that value was around 20 ohms, but i wouldn't swear to it...

Nothing like PME E54, i very much doubt you would feel any sensation on a TN-S.

As for an Electrode on a PME, for it to be any use you would be looking at very low single figures.

A lot of these Hot Tubs are class II as well.

 

[electric will]

Further back in this thread it was mentioned that someone had a small tingle while getting in and out with tncs to that why I've decided to tt. As long as I can get less than 199 ohms.

- - - Updated - - -

Only kidding about the 199. Don't start biting me

 

[SPARTYKUS]

Hot tubs are class II? Excellent.

 

[SPARTYKUS]

If you're getting a tingle somethings very wrong

 

[electric will]

Maybe small earth leakage from the element I'll find the post it wasn't me that said it.