Commercial deep fat fryer

[dave2]

Was asked by my local landlord to have a look at his new fryer as its tripping the 32A mcb.

Its cabled from cu to cooker switch via 6mm t&e and then to fryer in 2x 4mm t&e.

Further investigation reveals the appliance has 2 x 12kW seperate fryers with a total load of 63A! so no wonder it trips the mcb when both fryers are switched on together. Taking diversity into account it will still require almost 22kW

The cu (one of many in the premises) is protected by a 63A / 30mA rcd main switch which feeds 4 x 32A rings, 2x 20A radials and 3 x 6A lights so I doubt if he can add a 63A supply from here!

My advice is to request a further supply from dno and feed the fryer direct from its own db.

Has anyone any experience of theseheavy duty fat fryers?

Any comments on the best way to proceed.

 

[Revved Up Sparky]

Is it by any remote chance a three phase one that's been bodged to work on single phase ?. I remember attending a similar situation concerning a kitchen appliance tripping some years ago and that was what I found !.

 

[bluetof]

Cooker diversity calculation below:

The first 10amps then 30% of the remainder (+5 amps if 13 amp switched socket provided)

So 1 fryer is rated at 52 amps (roughly if no socket)

The first 10amps then 30% of 42 which is 12.6 amps.

Both added together gives the fryers a rating of 22.6 amps times 2 which is 45.2 amps. which gives you a rating of 10.4kw.

Upgrade the 4mm supply leads to 6mm and try a 50amp mcb on it, should be okay providing the cable run from CU to appliance isn't too far.

Personally I would try it on a 40A mcb

 

[Andy™]

Cooker diversity calculation below:

er... that doesnt work

for a cooker, there are many elements, each not likely to be on at the same time (for long anyway)

this is a fryer, which will most likely have only 1 element (possibly more if designed for SP & TP), which are likely to all be on at the same time. cant see any way which you could apply diversity... its either on, or its not

 

[bluetof]

Andy

If the element was always on with no thermostatic control then the place would burn to the ground - no need to worry abou cable sizes or the like ; -)

 

[Apache]

Use nothing else on the circuit and put your clamp meter around the tails for the DB? Try 1 element, then two. Find out what It really is drawing?

 

[dave2]

The manufacturer recommends 3 phase supply but they also say that single phase is still ok.

I dont like to go against manufacturers instructions and they categorically state a 63A supply.

Each fryer when used alone does not trip the 32A mcb but when both are switched on the mcb trips in about 10 seconds.I believe that there are 2 separate feeds to the appliance 1 for each fryer and that is why the original sparky installed 2 x 4mm t&e.

 

[gselectrical]

Re-wire it in 10mm? J

 

[batty]

AndyIf the element was always on with no thermostatic control then the place would burn to the ground - no need to worry abou cable sizes or the like ; -)

I agree with Andy on this one. How long do you think it will take for oil to get to temperature from cold anyway there must be a problem otherwise circuit breaker would not trip out.

 

[SPECIAL LOCATION]

Cooker diversity calculation below:The first 10amps then 30% of the remainder (+5 amps if 13 amp switched socket provided)

So 1 fryer is rated at 52 amps (roughly if no socket)

The first 10amps then 30% of 42 which is 12.6 amps.

Both added together gives the fryers a rating of 22.6 amps times 2 which is 45.2 amps. which gives you a rating of 10.4kw.

Upgrade the 4mm supply leads to 6mm and try a 50amp mcb on it, should be okay providing the cable run from CU to appliance isn't too far.

Personally I would try it on a 40A mcb

That is diversity for Cooking appliances in INDIVIDUAL HOUSEHOLD INSTALLATIONS..

These fat frier's are clearly not your average Individual Household appliance...

AND the title of the thread is "COMMERCIAL" deep fat fryer!!!!! :Blushing

If we are looking at diversity we would be into the next columns of page 97..

e.g. small shops, offices, businesses, boarding houses etc.. etc..

which is:-

100% of first appliance

80% of second appliance

60% of third appliance..

In this case.. 100% of 63A = 63A!

:_|

 

[bluetof]

Re-wire it in 10mm? J

No need to rewire in 10mm.

Fault protection.

The maximum length for a 6mm cable using a 50A MCB is;

Z41 - Ze / (R1 + R2)Cr

Z41 from table 41.3 for a 50A MCB = 0.92

Assume Ze at max TNCS 0.35

R1 + R2 from OSG 10.49 / 1000 = 0.01049

0.92 - 0.35 / 0.01049

So the maximum length for a 6mm cable to be covered by a 50A MCB is 54 metres, but for fault protection you have an RCD anyway

----------------------------------------------------------------------------------------------

Short circuit protection.

Using the same parameters.

Z41 - Ze / 2R1 Cr

R1 = 3.08 / 1000 = 0.00308 x 2 = 0.00616

0.92 - 0.35 / 0.00616

So for short circuit protection only a 6mm cable covered by a 50A MCB gives you a circuit length maximum of 92 metres. :z :good luck:

 

[Andy™]

AndyIf the element was always on with no thermostatic control then the place would burn to the ground - no need to worry abou cable sizes or the like ; -)

re-read what i said. the element is either on or off. so load is either 12KW or 0. you cannot just wire this as 8KW (or some other value)

would you apply diversity to a 10KW shower so you could wire it with 4mm and a 20A MCB?

 

[benji]

if its 3phase it could have three elements if so you could remove any links then you could take 3 x240v lines&neutrals to the elements,

just a thought?

yours benji

 

[septiclecky]

Re-wire it in 10mm? J

Still wouldn't stop the MCB trippng though

 

[bluetof]

Use nothing else on the circuit and put your clamp meter around the tails for the DB? Try 1 element, then two. Find out what It really is drawing?

Agreed

Put a clamp on meter on it and remove all doubt.

 

[benji]

can you give us the elect.spec. of the fryer &model

yours benji

 

[dave2]

Appliance is a Lincat OE7113/F TWIN FRYER--2x12kW

 

[bluetof]

http://tinyurl.com/ylcas9q

The technical data states that this model requires 2 single phase or 2, 3 phase supplies. Also states that the current is 34.8 amps per phase.

You are looking at another supply here mate - either that or he changes his fryer.

The 0E7105 twin fryer has 20.3 amps per phase.

Good luck anyway

 

[bluetof]

Oops that link previous didn't seem to work.

try this

http://www.carltonsales.co.uk/images/pdf/opus(14).pdf

Its page 14

 

[benji]

ok its 2x12kw 3 phase ,but are they 3x4kw linked together or just 1x12kw.

yours benji