KVA advice

[Bbracken]

Hi all I/m new to here and this is the first major installation of 3 phase and looking for advice

The unit has a incoming supply off 3 phase four wires with 2x 80amp and 1 x 100amp 1361 type 2 fuses. and used to be a truck haulage company

I am in the process of installing three, 3 phase ovens for the company which are all 14.5 kw each on a 3 phase supply.
With the other circuits the total we would be pulling would be around 82.2 kw total on balanced 3 phase.

At present we are running all but the three, 3phase ovens which are ready to be installed once confirmed.

The circuits are the following

3 x 3 phase 14.5kw ovens (to be added)
2 x 1 phase 6.5kw ovens
1 x 1 phase 9.5 kw dishwasher
1 x 3 phase 1.5kw mixer
2 x 1 phase 20amp radial circuit
1 x 1 phase 6 amp lighting circuit
1 x 1 phase CU unit of 50amp

The unit is for production of cakes therefore the ovens, dishwasher will be on most of the day.

We would be looking at adding one more oven of the same 14.5kw at a later stage.

Would the supply coming into the build need upgrading, if so which dept of the DNO would I need to contact.

Thanks

 

[Lucien Nunes]

At the moment, assuming the 80A fuses are increased to 100A, you have 69kVA available. Since most of the load is resistive heating, the power factor will be very close to unity so you could take it as 69kW.

Your 82kW doesn't seem to include any diversity at all. I have no knowledge of bakery diversity; you could use figures for commercial kitchens generally but as the main load is the ovens, I would consult the the oven manufacturer for typical figures for normal operation. My hunch is that it will be OK even with the four ovens but you should use the best available data to calculate rather than a hunch.

 

[plugsandsparks]

Do you have a picture of the service head and meter ?
The local DNO, depends which part of the country you are in

 

[Bbracken]

At the moment, assuming the 80A fuses are increased to 100A, you have 69kVA available. Since most of the load is resistive heating, the power factor will be very close to unity so you could take it as 69kW.

Your 82kW doesn't seem to include any diversity at all. I have no knowledge of bakery diversity; you could use figures for commercial kitchens generally but as the main load is the ovens, I would consult the the oven manufacturer for typical figures for normal operation. My hunch is that it will be OK even with the four ovens but you should use the best available data to calculate rather than a hunch.

thanks for the quick reply. the board is follows if this helps

its a 8way 3 phase wylex board. I have arranges the following circuits to balance the load

the ovens and mixer are on 3 phase using up 4 3 phase
then on
L1 brown I have Office CU 50Amp, Lights 6amp
L2 Black Dishwasher 9.5kw, Oven 6.5kw
L3 Grey 2x 20amp radial and oven 6.5kw

Im looking for diversity for ovens (still looking)

 

[Bbracken]

Do you have a picture of the service head and meter ?
The local DNO, depends which part of the country you are in

 

[Bbracken]

At the moment, assuming the 80A fuses are increased to 100A, you have 69kVA available. Since most of the load is resistive heating, the power factor will be very close to unity so you could take it as 69kW.

Your 82kW doesn't seem to include any diversity at all. I have no knowledge of bakery diversity; you could use figures for commercial kitchens generally but as the main load is the ovens, I would consult the the oven manufacturer for typical figures for normal operation. My hunch is that it will be OK even with the four ovens but you should use the best available data to calculate rather than a hunch.

thanks again for the advice looking at the `OSG its states business premises as 100% of largest then 80% or 2nd and 60% of rest. so for the 3 phase ovens I worked this to be 34.8kw

 

[plugsandsparks]

OK, thats an interesting setup, do you know where all the incoming cables come from. I think that meter is rated at 50A , is it a sub meter off another supply ?, is it an overhead supply ?

 

[Bbracken]

OK, thats an interesting setup, do you know where all the incoming cables come from. I think that meter is rated at 50A , is it a sub meter off another supply ?, is it an overhead supply ?

It is a overhead supply from a pole outside

 

[Bbracken]

It is a overhead supply from a pole outside

the meter now feeds a 3 phase Wylex board which I have now placed along side

 

[brianmoooore]

Are you taking the supply rating from what's written on the DNO holders, or from the fuses themselves?
That meter is definitely only rated at 50A per phase.

 

[Bbracken]

Are you taking the supply rating from what's written on the DNO holders, or from the fuses themselves?
That meter is definitely only rated at 50A per phase.

no the fuses were out when we took over the unit. The fuses are 80amp x2 and the 100amp> cause they were out I replaced the old board with the new one.

 

[Julie.]

It looks like the dno has removed the old red phase fuse holder and replaced it with a newer one, allowing the red phase (before your fuse) to feed somewhere else.

The meter is 50A so your maximum total load across all phases must be less than 50A per phase irrespective of the fuse size.

You need to contact the dno/supplier to upgrade the meter, and potentially the main supply.

 

[Bbracken]

It looks like the dno has removed the old red phase fuse holder and replaced it with a newer one, allowing the red phase (before your fuse) to feed somewhere else.

The meter is 50A so your maximum total load across all phases must be less than 50A per phase irrespective of the fuse size.

You need to contact the dno/supplier to upgrade the meter, and potentially the main supply.

thank you for your help. Ive just emailed Weston power but will call them in the morning. Thanks again

 

[plugsandsparks]

Yep, call WPG for 3 X 100A fuses, and then call "whoever client has contracted for an electricity bill" (NOT WPG) - for a new meter, all the new ones i have seen have been rated to 100A without CTs so you are not asking for anything special.

Good Luck