AFDD’s

[Carlosfandango]

I’m hoping to pick the brains of someone who can help me with a tender query for a commercial property. The designer has specc’d AFDD’s for all 44 outgoing ways on a three phase D.B. The specc’d board is a Hager, not that that really matters though. I’m not 100%, but I think AFDD’s are all 2 module size? Has anyone fitted out a board with these. If so, how do you go about doing it?? The tender is a lump sum, so I could just submit a quote using the price I have for the AFDD’s (£162 each!) and worry about it if I win the job?? Or I can quote for RCBO’s and explain the cost implication??? Any advise would be greatly appreciated!

 

[SparkySy]

Is there a specific reason why the designer has requested them for this property?
They are indeed 2module width I have never fitted any to their 3phase boards and from the way the terminals are set I wouldn't think it is possible.(I may be wrong it does happen)
It would be down to the designer and person ordering the work to agree a change in specification, I would find out why they have been asked for and then see if you can get the spec changed. Even if you quote for them the cost of them may be enough to get them changed!

 

[freddo]

The only 1 mod ones I've read about is Wylex and apparently they don't fit their 3ph boards! AFDDs for all circuits seems excessive!

 

[bill01803]

Just price as specified

 

[pc1966]

Going to cost!

Presumably no 3-phase loads, just a lot of single phase?

I think in Europe it is common for boards to have DP breakers due to a lot of TT use, so it might be worth a call to Hager to see if they have a EU 3-phase board that could take the AFDD with a common busbar. Also Schneider do a neutral bus arrangement for their TPN stuff, but I have no idea if they offer AFDD / RCBO modules to match (probably they do).

But that will mean 44 circuits at double-width module is 88 slots = 30 way TPN board!

Or you look to split it over several DBs, in which case you might get away with the Wylex 1-module in a standard CU. Depending on the layout it might be more efficient to have a MCCB board and local DBs.
[automerge]1591818895[/automerge]

Or I can quote for RCBO’s and explain the cost implication??? Any advise would be greatly appreciated!

It certainly is important to point out they won't get 44 AFDD in a single Hager TPN board as they are 2-module wide (biggest they do seems to be 18-way) and so you would need 2 boards of 16-way to get that lot in.

So the cost is not the only factor to raise, the planned site layout might not have made allowances for that, and you then have the possible issue of a separate TPN isolator to kill all in one go, or using one of the kits to connect one board to another daisy-chain (never used one so don't know quite how well it works).
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Also look out for other specified stuff, for example, you can't use the internal meter and SPD kit on the Hager TPN board, they suggest the separate 30cm high add-on board for the metering, or you use the sort of SPD kit for the dual-metered boards that takes up one of your 3-phase slots..

 

[Carlosfandango]

Going to cost!

Presumably no 3-phase loads, just a lot of single phase?

I think in Europe it is common for boards to have DP breakers due to a lot of TT use, so it might be worth a call to Hager to see if they have a EU 3-phase board that could take the AFDD with a common busbar. Also Schneider do a neutral bus arrangement for their TPN stuff, but I have no idea if they offer AFDD / RCBO modules to match (probably they do).

But that will mean 44 circuits at double-width module is 88 slots = 30 way TPN board!

Or you look to split it over several DBs, in which case you might get away with the Wylex 1-module in a standard CU. Depending on the layout it might be more efficient to have a MCCB board and local DBs.
[automerge]1591818895[/automerge]

It certainly is important to point out they won't get 44 AFDD in a single Hager TPN board as they are 2-module wide (biggest they do seems to be 18-way) and so you would need 2 boards of 16-way to get that lot in.

So the cost is not the only factor to raise, the planned site layout might not have made allowances for that, and you then have the possible issue of a separate TPN isolator to kill all in one go, or using one of the kits to connect one board to another daisy-chain (never used one so don't know quite how well it works).
[automerge]1591819103[/automerge]
Also look out for other specified stuff, for example, you can't use the internal meter and SPD kit on the Hager TPN board, they suggest the separate 30cm high add-on board for the metering, or you use the sort of SPD kit for the dual-metered boards that takes up one of your 3-phase slots..

There’s only two three phase loads, rest single phase. I’ll probably price it using the Schneider KQ boards. The SPD isn’t an issue, that will be fed off the panel board. The problem is if another firm just ends up pricing using RCBO’s only, that’s about 5 grand difference in cost!! A quick email to query it is the first port of call I think!

 

[Cookie]

Is there a specific reason why the designer has requested them for this property?
They are indeed 2module width I have never fitted any to their 3phase boards and from the way the terminals are set I wouldn't think it is possible.(I may be wrong it does happen)
It would be down to the designer and person ordering the work to agree a change in specification, I would find out why they have been asked for and then see if you can get the spec changed. Even if you quote for them the cost of them may be enough to get them changed!

Same question. Why spec them? AFDDs are pointless.

 

[Carlosfandango]

Just price as specified

I will, but if you read the post you’ll see that I was asking for information for fitting AFDD’s into a three phase d.b!

 

[westward10]

It should be noted Hager AFDDs do not incorporate rcd protection so this may muddy the waters if this is also a requirement. Crabtree Starbreaker AFDDs can be combined with an rcbo into a two module unit for consumer units however this is of no use to you. Eaton produce an AFDD combined with rcbo which is three module width. If Hager is the only option I would contact them as to how additional rcd protection can be added to their AFDDs.

 

[radiohead]

It should be noted Hager AFDDs do not incorporate rcd protection so this may muddy the waters if this is also a requirement. Crabtree Starbreaker AFDDs can be combined with an rcbo into a two module unit for consumer units however this is of no use to you. Eaton produce an AFDD combined with rcbo which is three module width. If Hager is the only option I would contact them as to how additional rcd protection can be added to their AFDDs.

Starbreaker are now single module combined RCBO/AFDD.

 

[pc1966]

Starbreaker are now single module combined RCBO/AFDD.

Same as the Wylex ones.

But last time I checked the Wylex compact RCBOs were not listed as compatible with their TPN boards, or I would have gone for that and been a happy and wealthier man with out needing separated RCCBs to get dual-pole switching so serious faults don't tip the incomer RCCB.

That might have changed, and you might find out be asking them, but my experience of recent Wylex technical support has been p*ss-poor even before lock-down

 

[static zap]

Any RFC in design !