odd one seen today, three FCUs each for a 3KW immersion on one 6mm radial

[westward10]

The last 500mm drops down inside a partition.

Without looking does that mean the ocpd is oversized for a 6.0 cable?

 

[GeorgeCooke]

If you put in a CU with 3 16 amp MCBs you don't need FCUs as well.

 

[GBDamo]

If it’s the solution it’s the solution ......

Why do you say it’s price prohibitive

If the customer won’t pay to do it properly , just walk away

I wish, I'm asked to make it work and given a spend limit. Running three new circuits is above that.

Not ideal is not necessarily non-compliant.

 

[GBDamo]

If you put in a CU with 3 16 amp MCBs you don't need FCUs as well.

I know but there already there with the flexes run in so rather than have to patch the holes, just use them.

 

[GBDamo]

Without looking does that mean the ocpd is oversized for a 6.0 cable?

No but close. Like I said upthread someplace, It's all clipped direct bar 0.5m but that will be by the time I've finished.

 

[Octopus]

I wish, I'm asked to make it work and given a spend limit. Running three new circuits is above that.

Not ideal is not necessarily non-compliant.

How much difference between doing it properly and budging it to the budget?

 

[Flanders]

I like George's idea and fit flex outlets where the original 13 amps spurs are , or is there no budget for parts

 

[GBDamo]

How much difference between doing it properly and budging it to the budget?

Properly as in your view? Which I don't necessarily disagree with.

or

Properly as in compliantly?

 

[GBDamo]

I like George's idea and fit flex outlets where the original 13 amps spurs are , or is there no budget for parts

I 'like' it too but aesthetics butter no parsnips.

 

[sparkdog]

Usually a 3KW element on an FCU results in an overheating and burnt out FCU before long. I would have a 16A MCB and DP switch for each.

 

[GeorgeCooke]

I know but there already there with the flexes run in so rather than have to patch the holes, just use them.

OK, consider this, 3kW at 240v is 12.5 amps. Your voltage may be above this at 245v so 12.76 amps. If the immersions are rated at 3kW at 230 volts we would have 13.04 amps at 230v or 13.6 amps at 240v, 13.9 amps at 245v. Don't forget the voltage is allowed to rise to 253v.

Anyway the 13 amp fuses are going to run hot at these sort of continuous loads with subsequent damage to the FCUs.

 

[GBDamo]

OK, consider this, 3kW at 240v is 12.5 amps. Your voltage may be above this at 245v so 12.76 amps. If the immersions are rated at 3kW at 230 volts we would have 13.04 amps at 230v or 13.6 amps at 240v, 13.9 amps at 245v. Don't forget the voltage is allowed to rise to 253v.

Anyway the 13 amp fuses are going to run hot at these sort of continuous loads with subsequent damage to the FCUs.

Is that maths right? should the Amps drop as the Volts rise?


Again, not disagreeing with you in principle but the same could be said for any Immersion connected via an FCU.

 

[Bellendian]

I'd be very surprised if bs1363 doesn't take into account permitted variations in the supply voltage.

That said, I always put immersions on a 16A breaker and a DP switch.

For some reason I tend to wire the circuit in 2.5 as well, even though I keep telling myself 1.5 would be fine!

 

[Octopus]

It’s not the current that ruins the switches, it’s the carp switches .....

 

[GeorgeCooke]

Is that maths right? should the Amps drop as the Volts rise?

It doesn't. I'm talking about 2 different immersions, one rated at 3kW 240v, and one rated at 3kW 230v.

 

[EbolaSideRoom]

Oughtn’t we be putting known fixed loads over 2kW on dedicated circuits any way?
I’m with Murdoch; do it right or not at all.

 

[GBDamo]

Oughtn’t we be putting known fixed loads over 2kW on dedicated circuits any way?
I’m with Murdoch; do it right or not at all.

They are, now, on dedicated circuits.

 

[sinewove]

They are, now, on dedicated circuits.

How about din rail box with 3 x b16 mcb,s?
S