Type-B for the sort of earth leakage current it can detect
C-curve for the speed of high-current overload
bi-directional
... which is a stunning combination to find in a single unit.
Don't believe what you see on the Screwfix site. I've complained to them about their haphazard way of mixing up the concepts of 'curves' and 'types'. However the polite email I received in response told me that customer support didn't understand the problem in the first place.
If you want an accurate description, first go to an electrical wholesaler such as CEF or TLC. Once you've found a device which appears to fit the required description, download the manufacturer's own technical specification to check. Note the manufacturer's part-number and use that when ordering!
This post was modified 2 hours ago 3 times by Transparent
It would appear that the installer has sent me an out of date spec document on the Vaillant heat pump. It now appears that I require a type B.
This means an additional consumer board needs to be fitted along with this new breaker.
From this table, I understand the following is needed in sequence to feed the heatpump:
the fuse/mcb is characteristic C - so C curve
the rcd is type B
An RCBO performs both functions.
The board you have includes several RCBOs and I assume all are being protected by a single B curve 40A MCB.
The heatpump cannot be fed by the same MCB. It needs a separate C curve MCB. But it also needs RCD type B.
If the MCB could be changed by a C curve one (and not invalidate manufacturers warranty, etc), perhaps you could avoid a separate Consumer unit.
But the main thing to focus is that a Type B RCD is needed. Wylex may be is a good brand that supplies them. It makes sense your electrician is suggesting they would use a separate CU (even if sometimes it could be avoided, the electrician that will sign it off ultimately decides).
8kW Solis S6-EH1P8K-L-PLUS hybrid inverter; G99: 8kw export; 16kWh Seplos Fogstar battery; Ohme Home Pro EV charger; 100Amp head, HA lab on mini PC
The board you have includes several RCBOs and I assume all are being protected by a single B curve 40A MCB.
STOP right there.
There is no such concept as an MCB protecting RCBOs.
Wait until I have time to clarify this later this evening.
Sorry if I have confused things. Here's a summary which I hope will help:
Vaillant require this breaker:
The installer is saying that the new breaker needs to be fitted in a new consumer unit as the breaker is larger than my current CU. This is full view of my CU.
This is inside, showing the breakers in question:
Hope this helps.
This post was modified 47 minutes ago by trebor12345
2024 build bungalow
Southern england 179 m2 High level of insulation Underfloor heating All 12 circuits are fully open all the time 1 thermostat in family room 7KW heat pump 50 litre buffer tank (4 port)
3.6KW solar panels Energy used by heating 2527 KWh - 7527 KWh (SCOP 3.5 approx)
