So, the two chip fryers for our new burger joint each have 2 x 6 kW heaters
in them, so a grand total of 24 kW. The electrician who is doing the work
(and whom I don't totally trust) is proposing feeding 4 x 6 kW feeds from
the board, to 4 isolation switches. This split across two phases. Sounds
reasonable so far ?? But, he's telling me that the RCD breakers to go in the
board, that he needs to feed these 4 lines, are about fifty quid apiece.
That seems a lot to me. What sort of breakers should these be ? Bog standard
single pole 32 amp ones ? Or am I missing something here ? I'm no expert in
electrical work, but I don't want to get charged for something that I don't
need. The board is brand new, just installed by the landlord's own
contractors. The electrician agrees that it is a "top quality unit that
complies with all the latest regs" - his words.

Opinions please ?

Arfa

Arfa Daily wrote:

The electrician who is doing
the work (and whom I don't totally trust) is proposing feeding 4 x 6 kW
feeds from the board, to 4 isolation switches. This split across two
phases. Sounds reasonable so far ?? But, he's telling me that the RCD
breakers to go in the board, that he needs to feed these 4 lines

Is he fitting MCBs (break on overload only), RCBs (unlikely as they
break on leakage current only), RCBs plus MCBs, or RCBOs (combined RCB/MCB)?

are about fifty quid apiece.

Price suggests RCBOs ... e.g.

http://www.neweysonline.co.uk/Circuit-Protection-Domestic-Protection-RCBO%27s/c02c02c01.r10.1/Search.raction

Andy Burns wrote:

Is he fitting MCBs (break on overload only), RCBs (unlikely as they
break on leakage current only), RCBs plus MCBs, or RCBOs (combined RCB/MCB)?

That'll teach me to type without my glasses on and eyes full of sleep,
read all occurrences of "RCB" in the above as "RCD" ...

"Andy Burns" wrote in message
o.uk...
Arfa Daily wrote:

The electrician who is doing
the work (and whom I don't totally trust) is proposing feeding 4 x 6 kW
feeds from the board, to 4 isolation switches. This split across two
phases. Sounds reasonable so far ?? But, he's telling me that the RCD
breakers to go in the board, that he needs to feed these 4 lines

Is he fitting MCBs (break on overload only), RCBs (unlikely as they
break on leakage current only), RCBs plus MCBs, or RCBOs (combined
RCB/MCB)?

are about fifty quid apiece.

Price suggests RCBOs ... e.g.

http://www.neweysonline.co.uk/Circuit-Protection-Domestic-Protection-RCBO%27s/c02c02c01.r10.1/Search.raction

Now that I don't know, Andy. Is there something that says it needs to be
these combo types, or is it just his opinion or what ? What is actually
required to comply with any regulations, and be 'sensibly' safe ? Initially,
he assumed that the total load on the fryers was 12 kW, and came back with a
quote for all the electrical work, which I thought was a bit steep, but we
needed it getting on with, and a friend had recommended him, so we said ok.
When we realised that he had specced it wrong, we told him, and he initially
said that *we* must have it wrong as that was far too much of a power
requirement. We assured him that it was right, and pointed him at the
website for the fryers, which said so. He then upped the quote by 300 quid
and said that this was because of the additional load now required. When I
queried the cost of this, he blustered and bumbled and said it was because
the breakers required were very expensive and he'd now got to put in two
more feeds and isolators. The run is about 6 metres back to a brand new
panel on a brand new three phase supply. The fryers are nothing more than a
sophisticated commercial version of the 3 kW deep fat fryers that we all
have sitting in our kitchens at home.

See :-

http://www.lincat.co.uk/products/sil...e-standing/j12

Arfa

Arfa Daily wrote:

"Andy Burns" wrote:

Is he fitting MCBs, RCDs, RCDs plus MCBs, or RCBOs

Now that I don't know, Andy. Is there something that says it needs to be
these combo types, or is it just his opinion or what ?

Well, I assume you'll have to (or want to) use RCD protection somewhere,
depends if you want overall protection (where if one item causes a
leakage trip, they will all be shut down) or individual protection (so
that only the faulty item is isolated)

What is actually required to comply with any regulations

Within a commercial kitchen, I'd have no idea.

and be 'sensibly' safe ?

One overall RCD and individual MCBs would be equally safe, but I assume
the reason for having two separate fryers is a certain degree of
independence, so would tend towards the RCBO route, though it will be
the most expensive.

On 21/05/2011 09:36, Andy Burns wrote:
Arfa Daily wrote:
and be 'sensibly' safe ?

No need for RCDs of any kind, provided all the following apply:

- TN-S or TN-C-S supply;
- all surface-wired (SWA, hi-tuf, conduit/trunking);
- nothing to the contrary in the appliance manufacturer's instructions;
- earth fault loop impedances (Zs) all within the usual limits;
- no socket-outlets on these circuits.

If you want belt and braces safety I'd go for supplementary bonding
across all the exposed metalwork in the working area - cheap and
effective. Make sure the Zs tests are done before connecting the
bonding though, otherwise a bad earth could be masked.

--
Andy

"Andy Burns" wrote in message
...
Arfa Daily wrote:

"Andy Burns" wrote:

Is he fitting MCBs, RCDs, RCDs plus MCBs, or RCBOs

Now that I don't know, Andy. Is there something that says it needs to be
these combo types, or is it just his opinion or what ?

Well, I assume you'll have to (or want to) use RCD protection somewhere,
depends if you want overall protection (where if one item causes a
leakage trip, they will all be shut down) or individual protection (so
that only the faulty item is isolated)

What is actually required to comply with any regulations

Within a commercial kitchen, I'd have no idea.

and be 'sensibly' safe ?

One overall RCD and individual MCBs would be equally safe, but I assume
the reason for having two separate fryers is a certain degree of
independence, so would tend towards the RCBO route, though it will be
the most expensive.


OK. Understood. Presumably, the main breaker / input switch on the panel
performs the RCD function ? Four baskets of chip frying capacity are needed
at busy times. Frozen chips rapidly drop the temperature of the oil, which
then has a recovery time of a couple of minutes, depending on how powerful
the heaters are. The 6 kW ones in the J12's are by no means the biggest you
can get. In takeaways, you will often see chips get moved from one fryer to
another during their cooking. This is to 'finish them off' in a fryer that's
at full temperature. It stops the chips being soggy. As to the situation if
one fryer became faulty in an RCD trip way. As we are intending having each
fryer circuit on its own isolator switch, I guess the faulty one could
effectively be 'taken off the board' by switching its feed off, allowing the
other three (or two possibly, depending on the nature of the fault), to
carry on working. Alternatively, if it is configured as four separate 6kW
feeds, each on its own breaker at the panel, the breaker for the appropriate
faulty circuit could just be flipped out, if the nature of the fault was not
just taking that breaker out on its own ?

Thanks for all the valuable input. I just like to understand these things,
and know that I'm not being taken for a mug. You wouldn't believe some of
the 'rogue traders' we've seen already, and although this electrician was
recommended to us by a friend, neither I nor the missus and daughter really
'took' to him from the start, and there's been a few little bits and pieces
in our dealings with him so far, that have done nothing to improve that
feeling. I'm sure you know how it is when you get this sort of feeling about
someone.

Arfa

Arfa Daily wrote:

Presumably, the main breaker / input switch on the panel
performs the RCD function ?

Well it could, or you might not have any, but as I say, I don't claim to
know if there are any specific requirements in a commercial setup, if Mr
Wade says RCD protection isn't mandatory for you, I'd tend to listen.

To know if your sparky is taking you for a ride you need to know what
type of breakers he is proposing and why, also what other protection
already exists on the installation. Not ideal if you don't entirely
trust who's working for you ...

we are intending having each fryer circuit on its own
isolator switch, I guess the faulty one could effectively be 'taken off
the board' by switching its feed off, allowing the other three (or two
possibly, depending on the nature of the fault), to carry on working.

Yes, if they have full isolators.

"Andy Wade" wrote in message
...
On 21/05/2011 09:36, Andy Burns wrote:
Arfa Daily wrote:
and be 'sensibly' safe ?

No need for RCDs of any kind, provided all the following apply:

- TN-S or TN-C-S supply;
- all surface-wired (SWA, hi-tuf, conduit/trunking);
- nothing to the contrary in the appliance manufacturer's instructions;
- earth fault loop impedances (Zs) all within the usual limits;
- no socket-outlets on these circuits.

If you want belt and braces safety I'd go for supplementary bonding across
all the exposed metalwork in the working area - cheap and effective. Make
sure the Zs tests are done before connecting the bonding though, otherwise
a bad earth could be masked.

--
Andy

Thanks. Good to have chapter and verse. Today, the electrician should have
been back, but he hasn't turned up, so that's him blown out of the water
anyway. At the moment, the extraction installation people are there
finishing up making their connections to the fused spurs which this guy had
put in ready for them. The daughter has just rung me to say that one of
these guys has just shown her that the neutral and earth were connected
backwards in one of these spurs. Even for this guy, I find that hard to
believe, but when he came the first evening, having already let us down
during the day because his "van had broken down", he did have another guy in
tow to help him, and I took to him still less ...

A guy that I do work for and trust implicitly, has just told me that his
stepson is a fully certified electrician, so I think I will get him in to
finish up, and check the rest of what's been done so far.

As to the installation, it is brand new. A new three phase supply and a new
board, put in by the landlords own contractors. The building was originally
2k sq ft, and the supply came into the left side of the building. The
building has now been divided into 2 x 1k sq ft, and we have taken the right
hand side unit. All of the existing electrics for our side of the building
were disconnected from the original board, and a new board was installed at
our side, and the original electrics reconnected to this. A new supply was
put in by NG or EON or whoever it is does the work on the supply grunt side
these days, and then a new three phase meter was fitted yesterday. All
proposed new wiring will be surface, and the circuits for the fryers will be
completely independent of any socket rings.

Given that we need to feed these two 12 kW fryers, which each have two 6 kW
heaters in them to make up that 12 kW, and that the manufacturers say that
they can be connected single or dual phase, what would you consider to be
the most versatile - from an isolation point of view - cost effective, and
load-sharing way of providing the necessary power ? Four 6 kW feeds split
across two phases as the original electrician was going to do, or some other
scheme ?

Thanks

Arfa

"Andy Burns" wrote in message
o.uk...
Arfa Daily wrote:

Presumably, the main breaker / input switch on the panel
performs the RCD function ?

Well it could, or you might not have any, but as I say, I don't claim to
know if there are any specific requirements in a commercial setup, if Mr
Wade says RCD protection isn't mandatory for you, I'd tend to listen.

To know if your sparky is taking you for a ride you need to know what
type of breakers he is proposing and why, also what other protection
already exists on the installation. Not ideal if you don't entirely
trust who's working for you ...

we are intending having each fryer circuit on its own
isolator switch, I guess the faulty one could effectively be 'taken off
the board' by switching its feed off, allowing the other three (or two
possibly, depending on the nature of the fault), to carry on working.

Yes, if they have full isolators.

Thanks

Arfa

John Rumm wrote:
On 21/05/2011 01:28, Arfa Daily wrote:

So, the two chip fryers for our new burger joint each have 2 x 6 kW
heaters in them, so a grand total of 24 kW. The electrician who is
doing the work (and whom I don't totally trust) is proposing feeding
4 x 6 kW feeds from the board, to 4 isolation switches. This split
across two phases. Sounds reasonable so far ?? But, he's telling me
that the RCD

You may be able to cope with two isolators - and basically a fryer on
each rather than a side of a fryer on each.

breakers to go in the board, that he needs to feed these 4 lines, are
about fifty quid apiece. That seems a lot to me. What sort of
breakers should these be ? Bog standard single pole 32 amp ones ? Or
am I missing

Since he is talking about feeding each fryer from two phases, he may
be proposing to use a 3P+N breaker rather than a pair of single phase
ones. Needless to say these breakers are more expensive.

(e.g. a Hager single phase MCB from TLC is three quid plus VAT, the 3P
version is ten times the price! The 3P MCBs also have a 10kA breaking
capacity while the single phase ones only 6kA normally. Higher
capacity may be required)

Looking at the spec he

http://www.lincat.co.uk/spec_sheets/S-LINKELECFRYJ.pdf

It seems to suggest you can either feed each fryer with two 26A single
phase feeds, or with two three phase feeds, in which case it draws
power from only two of the three phases, and takes 13A per phase.

(assuming the distribution of loads on the CU permits it, I would
probably opt for feeding fryer 1 left and right from two single phase
breakers on one phase, and the other fryer from two single phase
breakers on another phase.

Depending on how he does the wiring, you may not need RCD protection
for them anyway.

something here ? I'm no expert in electrical work, but I don't want
to get charged for something that I don't need. The board is brand
new, just installed by the landlord's own contractors. The
electrician agrees that it is a "top quality unit that complies with
all the latest regs" - his words.

Could you do us a photo of the CU?

Most of the commercial ones will take a mixture of breaker types
including single phase and three phase.


For the price the electrician has quoted you could run two sun main circuits
from 63A MCBS and fit 2 CUs!


--
Adam

On 21/05/2011 14:44, Arfa Daily wrote:

Given that we need to feed these two 12 kW fryers, which each have two 6
kW heaters in them to make up that 12 kW, and that the manufacturers say
that they can be connected single or dual phase, what would you consider
to be the most versatile - from an isolation point of view - cost
effective, and load-sharing way of providing the necessary power ? Four
6 kW feeds split across two phases as the original electrician was going
to do, or some other scheme ?

Assuming these are the major loads and everything else is fairly small
stuff I'd be inclined to run them in 2-phase configuration, using a
different combination of two phases, e.g.

- Fryer 1: L1+L2+N
- Fryer 2: L1+L3+N

then split the lighting and small power as evenly as you can across L2
and L3. Anything with a 3-ph motor in it will of course need all three
phases, and possibly N.

--
Andy

"Andy Wade" wrote in message
...
On 21/05/2011 14:44, Arfa Daily wrote:

Given that we need to feed these two 12 kW fryers, which each have two 6
kW heaters in them to make up that 12 kW, and that the manufacturers say
that they can be connected single or dual phase, what would you consider
to be the most versatile - from an isolation point of view - cost
effective, and load-sharing way of providing the necessary power ? Four
6 kW feeds split across two phases as the original electrician was going
to do, or some other scheme ?

Assuming these are the major loads and everything else is fairly small
stuff I'd be inclined to run them in 2-phase configuration, using a
different combination of two phases, e.g.

- Fryer 1: L1+L2+N
- Fryer 2: L1+L3+N

then split the lighting and small power as evenly as you can across L2 and
L3. Anything with a 3-ph motor in it will of course need all three
phases, and possibly N.

--
Andy

Thanks, as ever

Arfa

"John Rumm" wrote in message
...
On 21/05/2011 01:28, Arfa Daily wrote:

So, the two chip fryers for our new burger joint each have 2 x 6 kW
heaters in them, so a grand total of 24 kW. The electrician who is doing
the work (and whom I don't totally trust) is proposing feeding 4 x 6 kW
feeds from the board, to 4 isolation switches. This split across two
phases. Sounds reasonable so far ?? But, he's telling me that the RCD

You may be able to cope with two isolators - and basically a fryer on each
rather than a side of a fryer on each.

breakers to go in the board, that he needs to feed these 4 lines, are
about fifty quid apiece. That seems a lot to me. What sort of breakers
should these be ? Bog standard single pole 32 amp ones ? Or am I missing

Since he is talking about feeding each fryer from two phases, he may be
proposing to use a 3P+N breaker rather than a pair of single phase ones.
Needless to say these breakers are more expensive.

(e.g. a Hager single phase MCB from TLC is three quid plus VAT, the 3P
version is ten times the price! The 3P MCBs also have a 10kA breaking
capacity while the single phase ones only 6kA normally. Higher capacity
may be required)

Looking at the spec he

http://www.lincat.co.uk/spec_sheets/S-LINKELECFRYJ.pdf

It seems to suggest you can either feed each fryer with two 26A single
phase feeds, or with two three phase feeds, in which case it draws power
from only two of the three phases, and takes 13A per phase.

(assuming the distribution of loads on the CU permits it, I would probably
opt for feeding fryer 1 left and right from two single phase breakers on
one phase, and the other fryer from two single phase breakers on another
phase.

Depending on how he does the wiring, you may not need RCD protection for
them anyway.

something here ? I'm no expert in electrical work, but I don't want to
get charged for something that I don't need. The board is brand new,
just installed by the landlord's own contractors. The electrician agrees
that it is a "top quality unit that complies with all the latest regs" -
his words.

Could you do us a photo of the CU?

Most of the commercial ones will take a mixture of breaker types including
single phase and three phase.




--
Cheers,

John.


Thanks John. I'm going to pass all of this good info on to the guy who is
taking over.

Arfa

"ARWadsworth" wrote in message
...
John Rumm wrote:
On 21/05/2011 01:28, Arfa Daily wrote:

So, the two chip fryers for our new burger joint each have 2 x 6 kW
heaters in them, so a grand total of 24 kW. The electrician who is
doing the work (and whom I don't totally trust) is proposing feeding
4 x 6 kW feeds from the board, to 4 isolation switches. This split
across two phases. Sounds reasonable so far ?? But, he's telling me
that the RCD

You may be able to cope with two isolators - and basically a fryer on
each rather than a side of a fryer on each.

breakers to go in the board, that he needs to feed these 4 lines, are
about fifty quid apiece. That seems a lot to me. What sort of
breakers should these be ? Bog standard single pole 32 amp ones ? Or
am I missing

Since he is talking about feeding each fryer from two phases, he may
be proposing to use a 3P+N breaker rather than a pair of single phase
ones. Needless to say these breakers are more expensive.

(e.g. a Hager single phase MCB from TLC is three quid plus VAT, the 3P
version is ten times the price! The 3P MCBs also have a 10kA breaking
capacity while the single phase ones only 6kA normally. Higher
capacity may be required)

Looking at the spec he

http://www.lincat.co.uk/spec_sheets/S-LINKELECFRYJ.pdf

It seems to suggest you can either feed each fryer with two 26A single
phase feeds, or with two three phase feeds, in which case it draws
power from only two of the three phases, and takes 13A per phase.

(assuming the distribution of loads on the CU permits it, I would
probably opt for feeding fryer 1 left and right from two single phase
breakers on one phase, and the other fryer from two single phase
breakers on another phase.

Depending on how he does the wiring, you may not need RCD protection
for them anyway.

something here ? I'm no expert in electrical work, but I don't want
to get charged for something that I don't need. The board is brand
new, just installed by the landlord's own contractors. The
electrician agrees that it is a "top quality unit that complies with
all the latest regs" - his words.

Could you do us a photo of the CU?

Most of the commercial ones will take a mixture of breaker types
including single phase and three phase.


For the price the electrician has quoted you could run two sun main
circuits from 63A MCBS and fit 2 CUs!


--
Adam


That's kinda what we thought. Well, he's out of the picture now. I'm getting
another guy in, whose father I do work for, so I trust implicitly.

Arfa

On 21 May,
"Arfa Daily" wrote:

Given that we need to feed these two 12 kW fryers, which each have two 6 kW
heaters in them to make up that 12 kW, and that the manufacturers say that
they can be connected single or dual phase, what would you consider to be
the most versatile - from an isolation point of view - cost effective, and
load-sharing way of providing the necessary power ? Four 6 kW feeds split
across two phases as the original electrician was going to do, or some
other scheme ?

If each fryer is split across two phases then use the three phases for load
balancing. If you want each one completely independent, supply each one from
a single phase, but a different phase to the other. That is what I would do
with that load unless there are other compelling reasons.

If each would happily run on 6KW, then use all three phases. if they /need/
12Kw, then each on a single phase.

Three phase RCDs are available but as others have said (with provisos that
you seem to comply with) you don't absolutely need them. If each fryer was on
a single phase then single phase RCDs (which are cheaper) could be used.

--
B Thumbs
Change lycos to yahoo to reply

wrote in message ...
On 21 May,
"Arfa Daily" wrote:

Given that we need to feed these two 12 kW fryers, which each have two 6
kW
heaters in them to make up that 12 kW, and that the manufacturers say
that
they can be connected single or dual phase, what would you consider to be
the most versatile - from an isolation point of view - cost effective,
and
load-sharing way of providing the necessary power ? Four 6 kW feeds split
across two phases as the original electrician was going to do, or some
other scheme ?

If each fryer is split across two phases then use the three phases for
load
balancing. If you want each one completely independent, supply each one
from
a single phase, but a different phase to the other. That is what I would
do
with that load unless there are other compelling reasons.

If each would happily run on 6KW, then use all three phases. if they
/need/
12Kw, then each on a single phase.

Three phase RCDs are available but as others have said (with provisos that
you seem to comply with) you don't absolutely need them. If each fryer was
on
a single phase then single phase RCDs (which are cheaper) could be used.

--
B Thumbs
Change lycos to yahoo to reply

Hmmm. I don't understand enough about three phase to fully understand that.
I'm not really following the bit about them 'needing' 12 kW. If that is what
they are rated at, isn't that what they 'need' ? There are four independent
elements to feed - two in each fryer, one per tank. Each element is rated at
6 kW. I'm sure the electrician that we've got now will understand it all.
I'm meeting with him in the morning, so I'll see what he thinks is the best
feeding scheme, based on what he sees when he looks at the job.

Arfa

"John Rumm" wrote in message
...
On 23/05/2011 02:02, Arfa Daily wrote:


wrote in message
...
On 21 May,
"Arfa Daily" wrote:

Given that we need to feed these two 12 kW fryers, which each have
two 6 kW
heaters in them to make up that 12 kW, and that the manufacturers say
that
they can be connected single or dual phase, what would you consider
to be
the most versatile - from an isolation point of view - cost
effective, and
load-sharing way of providing the necessary power ? Four 6 kW feeds
split
across two phases as the original electrician was going to do, or some
other scheme ?

If each fryer is split across two phases then use the three phases for
load
balancing. If you want each one completely independent, supply each
one from
a single phase, but a different phase to the other. That is what I
would do
with that load unless there are other compelling reasons.

If each would happily run on 6KW, then use all three phases. if they
/need/
12Kw, then each on a single phase.

Three phase RCDs are available but as others have said (with provisos
that
you seem to comply with) you don't absolutely need them. If each fryer
was on
a single phase then single phase RCDs (which are cheaper) could be used.

--
B Thumbs
Change lycos to yahoo to reply

Hmmm. I don't understand enough about three phase to fully understand
that. I'm not really following the bit about them 'needing' 12 kW. If
that is what they are rated at, isn't that what they 'need' ? There are
four independent elements to feed - two in each fryer, one per tank.
Each element is rated at 6 kW. I'm sure the electrician that we've got
now will understand it all. I'm meeting with him in the morning, so I'll
see what he thinks is the best feeding scheme, based on what he sees
when he looks at the job.

You can basically choose to feed each element from one phase or two. If
you do it on one phase it will suck 26A on that phase. If you do it across
two it will draw 13A from each phase. There are pros and cons, but in the
end it will probably come down to which can be done with the cheapest
protective devices, and which best spreads the load over your three
phases. Given you have four loads and three phases, you are not going to
get a perfect distribution in this circumstance since each tank can only
use two phases at a time and not three.

One possible 3 phase allocation:

Tank Phases

T1 L1 L2
T2 L1 L3
T3 L2 L3
T4 L2 L3

Would give loads of 2 x 13A on L1, 3 x 13A on L2, and 3 x 13A on L3. You
would then probably want two three phase MCBs (£70 ish) - one per fryer.

Alternatively, using single phase:

Tank Phase

T1 L1
T2 L2
T3 L3
T4 L1

2 x 26A on L1, and 26A on each of the others. Four single phase MCBs (£15
ish) - allowing isolation of half a fryer.

Or:

T1 L1
T2 L1
T3 L2
T4 L2

2 x 26A on both L1 and L2, nothing on L3. Using two 63A MCBs (£8 - £30
ish) if available for your CU.


--
Cheers,

John.


Thanks John. All clear now. The new electrician turned up this morning to
cost and spec the job. I gave him a copy of the specs for the fryers, and he
took a lot of notes about the board and what else we needed. He has already
come back with a (very reasonable) price to sort out the three switched
spurs for the extraction equipment that the first guy had already made a
start on putting in, and his guy is there right now doing this. We are
expecting the quote for the rest of the work, which has a looser time
constraint on it, in the next couple of days. It will be interesting to see
what feeding scheme he comes up with for the fryers, based on what he saw
this morning, but unlike the other guy, I have total trust that whatever he
says, it will be appropriate for the circumstances, and realistically
priced.

Not least because me and his stepdad are good friends and business
associates, and that he went to school with my daughter !

Arfa