Oven Replacement - RCD?

[lozarus]

Afternoon all. Apologies if this is a stupid question. I'm currently half part way through completing 2391 (second exam tonight) - so may be getting myself in a tiz overthinking things.

Either way, thought I'd put it out to the group.

Task is: Straight swap of existing x5 ovens with new - "like for like", if you will. Albeit cooker plate to appliance is also in T&E and I intend to replace this with a more suitable product - namely HO7.

Earthing arrangement is: TN-S.

Environment is: Educational establishment, cookery rooms.

Circuits for the room originate in a local 3P+E MEM2 board, no RCD's. Ovens are simply domestic 1P+E bog standard, cheap household jobs, wired from C32's at the DB to 45a Isolators (no socket) at each station, cooker outlet below. Room is only about 10m long.

EICR from 2020 is available, but quite a few tests missed out - IE: Zs for each oven measured well within limit. No IR or R1+R2 undertaken - I'll be doing this anyway. It's all PVC T&E - mainly in metal trunking. I think it's loose behind the cabinets for the last few metres however.

My big question here is RCD. I could take the "like for like" approach and just straight swap the ovens out as "maintenance". But the environment (education) makes me think I really should be pushing for RCD's.

Further to this, manufacturers instructions state "Additional protection by RCD is recommended".

With that in mind, I'm convincing myself these really should be going onto RCD shouldn't they?

Or convince me I'm wrong. Sorry if I've overcomplicated a simple job here.

Thanks.

 

[default]

Afternoon all. Apologies if this is a stupid question. I'm currently half part way through completing 2391 (second exam tonight) - so may be getting myself in a tiz overthinking things.

Either way, thought I'd put it out to the group.

Task is: Straight swap of existing x5 ovens with new - "like for like", if you will. Albeit cooker plate to appliance is also in T&E and I intend to replace this with a more suitable product - namely HO7.

Earthing arrangement is: TN-S.

Environment is: Educational establishment, cookery rooms.

Circuits for the room originate in a local 3P+E MEM2 board, no RCD's. Ovens are simply domestic 1P+E bog standard, cheap household jobs, wired from C32's at the DB to 45a Isolators (no socket) at each station, cooker outlet below. Room is only about 10m long.

EICR from 2020 is available, but quite a few tests missed out - IE: Zs for each oven measured well within limit. No IR or R1+R2 undertaken - I'll be doing this anyway. It's all PVC T&E - mainly in metal trunking. I think it's loose behind the cabinets for the last few metres however.

My big question here is RCD. I could take the "like for like" approach and just straight swap the ovens out as "maintenance". But the environment (education) makes me think I really should be pushing for RCD's.

Further to this, manufacturers instructions state "Additional protection by RCD is recommended".

With that in mind, I'm convincing myself these really should be going onto RCD shouldn't they?

Or convince me I'm wrong. Sorry if I've overcomplicated a simple job here.

Thanks.

This is a commercial install. No 30mA protection need as long as all the bonding is as it should be.

 

[westward10]

The fact it is a school does not enforce the requirement for rcd protection. The fly in the ointment is the manufacturer 'recommending' rcd protection so read that as you will, recommending does not necessarily insist on it being done. Provided the existing devices satisfy ADS then to me it is fine.

 

[lozarus]

The fact it is a school does not enforce the requirement for rcd protection. The fly in the ointment is the manufacturer 'recommending' rcd protection so read that as you will, recommending does not necessarily insist on it being done. Provided the existing devices satisfy ADS then to me it is fine.

Yes, that does make sense. The reccomendation is indeed the main point that was bothering me. I suppose the theory behind this is to put the onus back on the installer.

 

[SparkyChick]

I would be very careful with the word 'recommended' right now... my understanding is that amendment 2 introduces a handy definition which implies "recommended" = "should". This has come to my attention specifically in relation to the installation of arc fault detection devices, but it's not beyond the realms of possibility that all recommendations are now must do's.

 

[westward10]

I agree you can see why they included it.

 

[Pretty Mouth]

The BSI have taken a common, well defined word, that everyone understood perfectly from an early age, and re-defined it to something that doesn't tally with the dictionary definition, so now we're all confused about it. If they mean 'should' then why not use the word should.

 

[SparkyChick]

The BSI have taken a common, well defined word, that everyone understood perfectly from an early age, and re-defined it to something that doesn't tally with the dictionary definition, so now we're all confused about it. If they mean 'should' then why not use the word should.

I would suggest it's the manufacturers sitting on the various committees that are driving things these days. Feels like things are changing just to sell more gear. I've got a situation at the moment where if I comply fully with the regs, a consumer unit that would cost £240 (this is for a BG board - only one that will fit with SPD and RCBOs) is going to cost well in the region of £850 because there are four socket circuits. I could potentially reduce that to maybe £550 by connecting three (old radial heater supplies with a single socket on each) of them together but overall, it's a ridiculous situation so now I'm thinking of having the client decline the AFDD option and record it as a departure. This is one bed cottage that needs a satisfactory EICR to comply with the Welsh rental laws. Currently two 3036 boards, everything is spot on apart from a socket outlet with a cracked face and rotting backbox... except it has no additional protection (has a 100mA upfront - TT earthing).

Recommended means you should really, but it's still optional.

As you say, they've redefined a word... still... that seems to be the game everyone is playing these days

 

[default]

I would suggest it's the manufacturers sitting on the various committees that are driving things these days. Feels like things are changing just to sell more gear. I've got a situation at the moment where if I comply fully with the regs, a consumer unit that would cost £240 (this is for a BG board - only one that will fit with SPD and RCBOs) is going to cost well in the region of £850 because there are four socket circuits. I could potentially reduce that to maybe £550 by connecting three (old radial heater supplies with a single socket on each) of them together but overall, it's a ridiculous situation so now I'm thinking of having the client decline the AFDD option and record it as a departure. This is one bed cottage that needs a satisfactory EICR to comply with the Welsh rental laws. Currently two 3036 boards, everything is spot on apart from a socket outlet with a cracked face and rotting backbox... except it has no additional protection (has a 100mA upfront - TT earthing).

Recommended means you should really, but it's still optional.

As you say, they've redefined a word... still... that seems to be the game everyone is playing these days

Is not having an AFDD a departure? And you could you fit an SPD in a separate unit before the boad? Or get them to sign saying they understand they should have it but do not won't it.

 

[SparkyChick]

Is not having an AFDD a departure? And you could you fit an SPD in a separate unit before the boad? Or get them to sign saying they understand they should have it but do not won't it.

I would say absolutely 100%, if you don't install AFDDs where they are required it's a departure and as I've outlined above, the regulations and the definition of "recommended" mean they are required in all domestic settings.

But that's just my interpretation, I'd be more than happy to be proven wrong.

 

[default]

I would say absolutely 100%, if you don't install AFDDs where they are required it's a departure and as I've outlined above, the regulations and the definition of "recommended" mean they are required in all domestic settings.

But that's just my interpretation, I'd be more than happy to be proven wrong.

Go back through the new regs. SPDs a must or wavier. AFDDs still just a bog standard recommendation with no caveat.

 

[timhoward]

Go back through the new regs. SPDs a must or wavier. AFDDs still just a bog standard recommendation with no caveat.

Look again!

 

[default]

Look again!

So your saying all new installations, DB changes you have to install AFDDs. EICRs, what code 2/3. Your wrong. Not mandatory.

 

[default]

So your saying all new installations, DB changes you have to install AFDDs. EICRs, what code 2/3. Your wrong. Not mandatory.

Show me where

 

[SparkyChick]

I don't have the BBB yet, but if this is what the regs actually say...

"Regulation 421.1.7 now states:

Arc fault detection devices (AFDD) conforming to
BS EN 62606 shall be provided for single-phase
AC final circuits supplying socket-outlets with a rated
current not exceeding 32 A in:

• Higher Risk Residential Buildings (HRRB)
• Houses in Multiple Occupation (HMO) i
• Purpose-built student accommodation ii
• Care homes iii

NOTE 1: Higher Risk Residential Buildings are assumed to
be residential buildings over 18 m in height or in excess of
six storeys, whichever is met first. It is anticipated that in
many areas higher risk residential buildings will be defined in
legislation which can be subject to change over time, as well
as in risk management procedures adopted by fire and rescue
services. Current legislation should be applied.

For all other premises, the use of AFDDs conforming
to BS EN 62606 is recommended for single-phase
AC final circuits supplying socket-outlets not
exceeding 32 A.

Where used, AFDDs shall be placed at the origin
of the circuit to be protected.
The use of AFDDs does not obviate the need to apply
one or more measures provided in other clauses in
BS 7671.

NOTE 2: For busbar systems conforming to BS EN 61439-6
and Powertrack systems to BS EN 61534, the AFDD may be
placed at a location other than the origin of the circuit."

Thats taken from this:-

https://www.beama.org.uk/static/60aec0d0-e6c8-4ca9-b486fb8a843d0c55/AFDD-fact-sheet-3-BS-7671-AMD2.pdf

Which also clarifies the "recommended = should".

I'd say there's no room for a choice in there.

 

[timhoward]

So your saying all new installations, DB changes you have to install AFDDs. EICRs, what code 2/3. Your wrong. Not mandatory.

No I'm not saying that.
Read 421.1.7
Note the word "shall".
Your original generalisation was not true.
What you guessed I was saying is also not true.

 

[DPG]

What a ridiculous situation. Obviously this is going to cause confusion.

I'd like to meet whoever approved that line about recommended=should and use him to test my AFDDs

 

[nicebutdim]

One point that's worth making is this 'clarification' of 'recommended' comes from a trade association and not the IET.

 

[default]

I don't have the BBB yet, but if this is what the regs actually say...

"Regulation 421.1.7 now states:

Arc fault detection devices (AFDD) conforming to
BS EN 62606 shall be provided for single-phase
AC final circuits supplying socket-outlets with a rated
current not exceeding 32 A in:

• Higher Risk Residential Buildings (HRRB)
• Houses in Multiple Occupation (HMO) i
• Purpose-built student accommodation ii
• Care homes iii

NOTE 1: Higher Risk Residential Buildings are assumed to
be residential buildings over 18 m in height or in excess of
six storeys, whichever is met first. It is anticipated that in
many areas higher risk residential buildings will be defined in
legislation which can be subject to change over time, as well
as in risk management procedures adopted by fire and rescue
services. Current legislation should be applied.

For all other premises, the use of AFDDs conforming
to BS EN 62606 is recommended for single-phase
AC final circuits supplying socket-outlets not
exceeding 32 A.

Where used, AFDDs shall be placed at the origin
of the circuit to be protected.
The use of AFDDs does not obviate the need to apply
one or more measures provided in other clauses in
BS 7671.

NOTE 2: For busbar systems conforming to BS EN 61439-6
and Powertrack systems to BS EN 61534, the AFDD may be
placed at a location other than the origin of the circuit."

Thats taken from this:-

https://www.beama.org.uk/static/60aec0d0-e6c8-4ca9-b486fb8a843d0c55/AFDD-fact-sheet-3-BS-7671-AMD2.pdf

Which also clarifies the "recommended = should".

I'd say there's no room for a choice in there.

Wow. Sorry dude. Need to look more into that. Need to see if we're just looking at new builds. And 18m is pretty high. I do mainly EICRS so need to see where this sits. Again, apologie

 

[timhoward]

Which also clarifies the "recommended = should".

I would take that clarification with a ton of salt.

Page 18 of the new regs book has a little table. The 2nd column should be the first column, as the intent is to translate the verbal form in BS7671 to an implication.
It says "Shall" is a requirement and normative, and "Should" is a recommendation (and is not normative)

If one studies the definitions on page 18 of Guidance, Normative Element, Requirement, and Recommendation I cannot see how anyone would conclude:

There is a misleading view being communicated within the industry that use of such terms as ‘recommended’, ‘additional’ and ‘specified’ demotes the requirements within the associated regulations.

In particular, Recommendation is ONE possibility and does not exclude other possibilities (including doing nothing)