Went to a mates hot tub today...

[Dunx]

Unfortunately it is not working! He said the MCB went bang several times. So rahter than call me he called the hot tub people, they came and tested the tub, which was ok and took a transformer away for testing. This was also ok. Tub people said to my mate you better get the wiring checked!

So I pop out, 40A type B mcb, 2.5mm SWA about a 30mt run with 3 junction boxes on route.

R1 +R2 + 0.54, I/R 299 all round. Very odd. Start going through the JB's and found the second one completely melted inside. 10A [?] connector blocks used, whatever they were was way too small. Interesting tho that all the 'standard' tests gave a clean bill of health.

Anyway he is selling up and I have told him i am not reconnecting as I think the cable is too small. Not sure on the start up load but it looks a BIG pump plus the heater. Contacting the makers tommorow.

Dunx

 

[steptoe]

Unfortunately it is not working! He said the MCB went bang several times. So rahter than call me he called the hot tub people, they came and tested the tub, which was ok and took a transformer away for testing. This was also ok. Tub people said to my mate you better get the wiring checked!So I pop out, 40A type B mcb, 2.5mm SWA about a 30mt run with 3 junction boxes on route.

R1 +R2 + 0.54, I/R 299 all round. Very odd. Start going through the JB's and found the second one completely melted inside. 10A [?] connector blocks used, whatever they were was way too small. Interesting tho that all the 'standard' tests gave a clean bill of health.

Anyway he is selling up and I have told him i am not reconnecting as I think the cable is too small. Not sure on the start up load but it looks a BIG pump plus the heater. Contacting the makers tommorow.

Dunx

and what current do you actually think a 2.5mm SWA CAN carry?????

headbang

 

[Zeespark]

What is the In and what curve/mcb type is needed?

AndyGuinness

 

[Dunx]

Hi,

Well its clipped direct and partly under the ground so say 36amps. Not sure on In, contacting the manufactures tommorow for the spec.

 

[NozSpark]

I'd think the filters were blocked ; )

 

[steptoe]

Hi,Well its clipped direct and partly under the ground so say 36amps. Not sure on In, contacting the manufactures tommorow for the spec.

either it is or it isnt?

so, will 2.5 SWA installed in the method you describe carry 40A or not? or what is its max CCC for the installation method?

after all, it is protected by a 40A OCPD.

 

[Dunx]

Steptoe you are being a little spiky? The reason I didn't reconnect was a] I wasn't sure b] it was nearly 7pm and c] I didn't know what the various loads of the tub were. A lot of weight apears now to be given to manuacturers recommendations so it seem a fair call to wait until tommorow. Oh and see what fellow sparks thought about it!

 

[steptoe]

right, no probs Dunx,

but I woulda thought it was a pretty reasonable guess that the cable couldnt carry 40A,

and a very quick check of your regs could confirm or deny this.

its not rocket science, and its certainly not something I would have thought a spark would be asking about, if a straight forward single phase circuit of 40A can be run on a 2.5 SWA cable that is buried in a duct.

the loads of the tub are absolutely nothing to do with this,

the MCB is there to protect the cable.

 

[Dunx]

Not sure we are on the same path here Steptoe! I know it wont take 40 amps FFS,[thats why I didn't reconnect, see first post] what I don't know and it is absolutely pertinent, is what is the load applied to the cable. Lets say its only 20amps max, the MCB is changed for the correct one for the CC of the cable.

 

[Doc Hudson]

A 2.5mm with 40A MCB protection does sound a little ambitious to say the least. I can understand Steptoes concerns as the MCB is to protect the cable not the load. I just wonder if this has been upgraded to a 40A MCB because of repeated problems in the past with smaller rating MCB's fitted?

Doc H.

 

[Zeespark]

If thats the case Doc, then the circuit should be redesigned from scratch, which is what I would have advised the customer had I have been in Dunx's position.

AndyGuinness

 

[ianmacd]

Maybe the cable is designed to heat the tub at the same time

 

[Dunx]

He is a mate and I have diplomatically told him its sh**e. Its been wired in 3 bits, wrong size cable, different types of junction boxes, different sizes of connector blocks, its not buried properly. What pains me more is that He asked me to give him a price a few years ago and he turned it down. He now says that a 'relation' of his ex partner did it.

He has now agreed for it to be disconnected and he is selling the house without it. F**k that was a tough

 

[ianmacd]

Don;t hold your breath. Bet he hasn't got an EIC or a building regs compliancy cert for it too.

 

[Doc Hudson]

Unbelievable! Mate or no mate, if something is wired in a dangerous manner I wouldn't hold any punches, tell them the truth straight. I doubt if any real friend would lend you a car with bald tyres, yet somehow they accept dangerous electrics. It must be down to the invisibility of electrical current?

Doc H.

 

[ianmacd]

Unbelievable! Mate or no mate, if something is wired in a dangerous manner I wouldn't hold any punches, tell them the truth straight. I doubt if any real friend would lend you a car with bald tyres, yet somehow they accept dangerous electrics. It must be down to the invisibility of electrical current?Doc H.

Or the lack of appreciation of just how little of it it takes to kill someone. 40A would be enough to kill 700+ people yet people treat it with such little regard. I guess their thinking is, well its not like its gas or something else dangerous. headbang

 

[a1]

What pains me more is that He asked me to give him a price a few years ago and he turned it down.

Then my price would double!

He now says that a 'relation' of his ex partner did it.

Make that Triple!