8.5 kw shower on old red/blue 6mm

[stratplus]

Coming across a few of these. Very small run of cable as cu is in kitchen just below bathroom but should be 10mm cable. Did the old cable used to be slightly bigger than the new stuff?

 

[Plonker 3]

How olds the cable?

 

[Badged01]

If you have the old stranded 7/044 its nearer 7mm!

 

[stratplus]

If you have the old stranded 7/044 its nearer 7mm!

Stranded, showers been in 10 yrs approx. Connector block melted at the incoming phase.

 

[Plonker 3]

What connector block? Has the circuit been extended?

 

[HappyHippyDad]

Stratplus, why do you think it should be 10mm cable? In certain conditions, small run and correct reference method 6mm will be ok for a 8.5Kw shower.

 

[Badged01]

And if its old cable, when the shower was installed it was probably something like 6.5kW ....... and has been upgraded since!

 

[jackhammerJIM]

What reference method for the cable run ?

 

[stratplus]

What connector block? Has the circuit been extended?

Connector block in electric shower where cable joibs shwr.

 

[stratplus]

Stratplus, why do you think it should be 10mm cable? In certain conditions, small run and correct reference method 6mm will be ok for a 8.5Kw shower.

Worked it out to 10mm. Cable run is ok and distance but concerned about melted cable connector block.

 

[jackhammerJIM]

show calculations

 

[HappyHippyDad]

Worked it out to 10mm. Cable run is ok and distance but concerned about melted cable connector block.

When you say 'cable run is ok', what reference method is the cable run? Also how did you get to 10mm? 6mm clipped direct would give you 46A to play with and you need 37A (A big assumption of clipped direct though!).

If the reference method is ok then the melted connector cable block might be poor connections? Also what sort of connector block was used? What do you think the rating of the terminals are? Could be they were not suitable?

 

[Andy78]

Worked it out to 10mm. Cable run is ok and distance but concerned about melted cable connector block.

What are your thoughts as to the cause of this fault ?

 

[NickD]

What are your thoughts as to the cause of this fault ?

I reckon, right, that it got too warm somehow.

 

[Andy78]

What are your thoughts as to the cause of this fault ?

I reckon, right, that it got too warm somehow.

Clearly because it needs a larger cable ...... Right ?

 

[PEG]

...Although playing devils advocate...correctly sized cable can generate heat when terminated poorly...just sayin...

 

[Badged01]

or a loose connection?

 

[Hawkmoon]

...Although playing devils advocate...correctly sized cable can generate heat when terminated poorly...just sayin...

just sayin....right

 

[telectrix]

new connector block in shower. re terminate if cable ends are OK. assuming ref. method is C. 6mm is perfectly adequate for the load.

 

[NickD]

Clearly because it needs a larger cable ...... Right ?

Well, the connector block melted cos the connector block got too warm, innit. Maybe it got warm by itself. Maybe something else made it warm. Maybe all the atoms in it just decided to have a bit of a disco and bounce around a lot to that ol' Brownian beat. It's difficult to know.