Energy efficiency of MCB's

[Marvo]

Something that came to my attention recently was an MCB with an efficiency rating and a predicted KWh decade energy loss figure for the OCPD itself. Do the UK consumer units ever come with efficiency ratings?

I guessed this was in response to some new EU or US regs regarding supply or transmission efficiency but it's not something I've personally come across before. Are there new regs regarding this that you know of? If so I'd be interested to read them.

We factor in obvious losses such as cable losses and motor losses when designing systems but actual switchgear losses (excluding VFD efficiencies etc) are something we've not worried about too much.

 

[Lucien Nunes]

Not a big deal IMHO, at a worst case loss of 0.05% of load power at full load on a 230V circuit, or 0.025% at a more representative half load. Of greater importance is that MCB's low breaking capacity of 3kA which suggests a basic or low-cost construction. The 15A rating and type 3 hint at an older design.

I expect the percentage loss is greater for small MCBs, as the heat power required to operate the thermal trip remains fairly constant but the maximum load power reduces. Breaker loss is also an argument in favour of SPSN types over DP for single-phase applications where polarity is predictable - you still get DP isolation but without the added dissipation of the heater in the neutral.

 

[Darkwood]

Probably EU tangle of red tape asking for all electrical goods to now have a Energy rating, clearly this shows the extent of goods effected and the millions wasted including them in the regulation, even once we have left the EU we will still see all this as we trade with them and have to comply.

Just waiting for them to start slapping energy ratings on my piezo lighter.

 

[Lucien Nunes]

To be fair, in this case it's an African-made breaker that doesn't seem to be to an EU spec. I haven't bought any small MCBs for a year or so - are we seeing these ratings in the UK?

 

[Marvo]

As you say Lucien, the 0.05% losses aren't much in the larger scheme of things but I guess if there's 10 MCB's in a CU/DB it could amount to almost half a kilowatt hour per day.

The MCB is the latest design with the 3 position toggle (on-->trip-->off) and 3kA is the lowest Icn rating, 5KA and 10KA are also available in the same form factor.

 

[mattg4321]

6KA is by far the most common across the board Lucien.

The only time I think I've seen less than that is on a Proteus RCBO recently - think it was 4KA.

Not specified by me I hasten to add! Don't buy any CEF own brand tat if I can help it!

 

[Lucien Nunes]

I meant the efficiency ratings, not the breaking currents - don't recall seeing an efficiency sticker on 60898s bought in the UK but I haven't bought any for a while.

4kA? I don't think I've ever installed an MCB of lower than 6kA in the last 20 years except in existing legacy systems like C50. That's why I was surprised about the MCB in the pic above.