Separate Arc fault protection devices not needed with RCD's?

[Sparkswillfly]

Just thought I'd provide an update, I have since upgraded the switchboard with the full AFDD detection.(buy once, cry once, if you're going to the trouble of upgrading the board, may as well go the whole hog) Only real issue was the lights tripped the RCD straightaway, something about a neutral removed from one circuit, I didn't really understand that part, and it was quickly fixed.

The day after installation, I've gone and identified which outlets etc on which circuits as its a useful thing to know if you ever have to isolate just one circuit. The interesting thing is, some items are now paired differently than on the old board eg in some cases, outlets that were previously on the same circuit are now on separate circuits, and those which were previously on separate circuits now are on the same circuit. The washer and dryer now share a circuit with two bedroom outlets whereas those 2 bedroom ones were previously separate from the laundry outlets. The lights were all previously on one breaker, now they're split between 2 AFDDs

Is it common for the circuit 'allocation' to be changed when getting a new switchboard? Do I need to be concerned and do I need to call the electrician back?

 

[Electrics]

Am i right in thinking these AFDD devices are only going to come in handy at the CU end where a wire isn't properly terminated?

 

[telectrix]

Just thought I'd provide an update, I have since upgraded the switchboard with the full AFDD detection.(buy once, cry once, if you're going to the trouble of upgrading the board, may as well go the whole hog) Only real issue was the lights tripped the RCD straightaway, something about a neutral removed from one circuit, I didn't really understand that part, and it was quickly fixed.

The day after installation, I've gone and identified which outlets etc on which circuits as its a useful thing to know if you ever have to isolate just one circuit. The interesting thing is, some items are now paired differently than on the old board eg in some cases, outlets that were previously on the same circuit are now on separate circuits, and those which were previously on separate circuits now are on the same circuit. The washer and dryer now share a circuit with two bedroom outlets whereas those 2 bedroom ones were previously separate from the laundry outlets. The lights were all previously on one breaker, now they're split between 2 AFDDs

Is it common for the circuit 'allocation' to be changed when getting a new switchboard? Do I need to be concerned and do I need to call the electrician back?

the electrician may well have rearranged the circuits in order to prevent a nuisance trip from taking out all circuits in one area,and to spread the loadsmore evenly across the MCBs etc. I'd not worry.

 

[Mikegh]

Am i right in thinking these AFDD devices are only going to come in handy at the CU end where a wire isn't properly terminated?

They should detect arc faults anywhere on the circuit afaik

 

[littlespark]

They should detect arc faults anywhere on the circuit afaik

except in an rfc. if one leg is still connected, and the other is arcing.

 

[pc1966]

except in an rfc. if one leg is still connected, and the other is arcing.

Generally you won't see an arc as the voltage between the broken end points in an open RFC is typically only a couple of volts max. The still should trip if it is a series arc on an appliance cable though (if big enough, as John Ward showed they don't really do small arcs well).

But it does point out that they don't stop an overloaded cable getting hot and even starting a fire, just so long as no arcing is involved...

 

[freddo]

What brand of consumer unit was used? Never seen an AFDD in real life.

 

[Sparkswillfly]

What brand of consumer unit was used? Never seen an AFDD in real life.

Schneider electric