Need to install a socket circuit for shop fridges

[FrenchConnection]

Hi All,

I need to install a socket circuit for glass fronted fridges in a shop. Following the technical specifications book of the fridges, each one needs a 13A supply.

Do I need to install one socket (fridge) per 13A fuse or I can install several sockets on one circuit?

What s the regulations for this?

Thanks

 

[JohnD]

you're installing circuits, but you are not an electrician, right?

 

[Taylortwocities]

Untitled

• Taylortwocities
• 24 Jan 2010
• 4

 

[ericmark]

There must be some diversity it is unlikely that all the freezers would normally all start together except after a power cut and this must be worse case scenario.

32A is the maximum for ring or radial so worse case your looking at three units per 32A MCB and this would mean with multi units very easy one could exceed the current on main incoming fuse.

In real terms where a 13A supply is called for the unit only uses around 4.5A and when I had a similar problem I used the timers of a star delta starter to set a sequence so on power on there was around a 10 second delay as each socket to activated that way a 32A supply could run 8 units rather than 3 which is more reasonable. 4 contactors were used the first 2 switching on 2 units the last two just one at a time so after a power failure the first two units were without delay then 10 seconds for next 2 etc.

The next 8 would have had different time settings so that way one can switch on 24 units without getting over a 90A surge.

As of course the number of units increases it becomes more cost effective to use a PLC and relays rather than contactors each with their own timer and with the advances in controllers likely over 6 units then one would use a PLC.

However this is hardly a DIY job and I would advise professional questions like this should be directed to a professional site. It is possible considering how many shops have rows of fridges or freezers that there is a pre-made timer on the market to allow a sequenced start after a power failure.

 

[ban-all-sheds]

Do I need to install one socket (fridge) per 13A fuse or I can install several sockets on one circuit?

No, you need to get someone who knows what they are doing to do the job.

An electrician would be a good idea.

 

[MalcofArabia]

How many fridges are there?

Is there a 3 phase supply in the shop?

If there is and you have say 6 fridges wouldn't it be better to balance them 2 on each phase.

Are you going to RCD protect them? As fridges have High current leakages if you RCD them you may find they trip a lot.

So you may want to think about a design that does not use sockets,

The permutations are innumerable would it not be best to leave it to someone that could design the installation for you.

 

[Steve]

It is possible considering how many shops have rows of fridges or freezers that there is a pre-made timer on the market to allow a sequenced start after a power failure.

Nope. Most proffesional commercial refrigeration installs now use cat5 networked controllers linked to an RDM - remote data manager.

From the RDM, one can program the units set points, defrost times, make sure not too many call for refrigerant at any one time (placing too much demand on the compressor pack or indeed the mains supply), monitor the pack temperature, the ambient indoor and outdoor temperature.

Very clever stuff.

Oh, and it has the capacity to get the staff out of bed at 2am when any units go high temperature.

@ the OP, just buy a couple of 4 gang trailing sockets and use them. If the chillers are glass door single bay affairs, the wattage wont be much more than 300 watts.

 

[ColJack]

OP, you are obviously not competent to do this so get someone who is..

 

[ericmark]

It is possible considering how many shops have rows of fridges or freezers that there is a pre-made timer on the market to allow a sequenced start after a power failure.

Nope. Most proffesional commercial refrigeration installs now use cat5 networked controllers linked to an RDM - remote data manager.

From the RDM, one can program the units set points, defrost times, make sure not too many call for refrigerant at any one time (placing too much demand on the compressor pack or indeed the mains supply), monitor the pack temperature, the ambient indoor and outdoor temperature.

Very clever stuff.

Oh, and it has the capacity to get the staff out of bed at 2am when any units go high temperature.

I had thought some form of telemetry would be used. I was working where there was 24 hour staff present so no need for that but were considering the use of SCARDA so it could be monitored in the office.

I remember looking at the costs for fitting some timers and temperature control and we realised it was cheaper to use a PLC than to use the little square timers as soon as 4 were required and so if there was any re-furbish then the timers etc would be scrapped.

As to the original question he has not added anything since first post and although likely he is a chancer I feel it is wrong to assume he is without any real evidence.

We all start somewhere and I was lucky to serve my time commercial but have met many very good electricians who have spend most of their time on new houses where everything was pre-designed and really all they did was follow a plan. They soon picked up other skills but did need some guidance.

I still remember the first time I came across ASi system and as with Probus and many others I have since worked on 100+ inputs and outputs on two (4 including power) wires and it transformed the whole idea of machine control.

It was a long time ago when I first trained and even if we were taught it in college to remember a college lecture if one has never needed the skills is hard. I have even met electricians who could not remember ohms law!

Seems in USA they use a type of PLC to control items in a house and it's all modular can you imagine what it would be like if we were hired to repair some US military housing! We would also be scratching out heads. Yes sure we would work it out but also sure we would if we could ask questions which to those who know it all would I am sure seem silly.

 

[Steve]

Aye, in my shop, there are four ethernet switches located around the place (in typically obscure places for a refrigeration install), and one RDM. There are 48 units in total, but this number includes the pack and other monitors.

Every fridge has a controller and a few relays.

Overnight, the RDM controls the fridges so that the beer, wine and pop fridges shut off overnight. The fans run, but the refrigerant valves stay closed between 10pm and 8am.

It also controls the fridge lights so all lights go off between 10pm and 8am. This is what one of the relays is for in each unit. Theoretically a different type of unit controller could be plugged into the RDM and it could control heating, store lights, air con. But its kept seperate to keep the refrigeration guys happy.

If our fridges were really good, the RDM could control the night blinds to come down at closing time too. But our fridges are quite old and have manual night blinds! About 50 of them!

 

[ricicle]

but were considering the use of SCARDA so it could be monitored in the office.

SCADA

 

[ban-all-sheds]

As to the original question he has not added anything since first post and although likely he is a chancer I feel it is wrong to assume he is without any real evidence.

Be realistic Eric.

This:

I need to install a socket circuit for glass fronted fridges in a shop. Following the technical specifications book of the fridges, each one needs a 13A supply.

Do I need to install one socket (fridge) per 13A fuse or I can install several sockets on one circuit?

What s the regulations for this?

doesn't read as if he's a properly qualified and experienced commercial electrician.

We all start somewhere and I was lucky to serve my time commercial but have met many very good electricians who have spend most of their time on new houses where everything was pre-designed and really all they did was follow a plan. They soon picked up other skills but did need some guidance.

Until they no longer need guidance on fundamental things they should not be selling their services.

I still remember the first time I came across ASi system and as with Probus and many others I have since worked on 100+ inputs and outputs on two (4 including power) wires and it transformed the whole idea of machine control.

That's a very different matter from

"Do I need to install one socket (fridge) per 13A fuse or I can install several sockets on one circuit?

What s the regulations for this?"

I have even met electricians who could not remember ohms law!

Then they absolutely should not be working as electricians. No discussion needed - drum them out of the trade. End of, goodbye.

Seems in USA they use a type of PLC to control items in a house and it's all modular can you imagine what it would be like if we were hired to repair some US military housing! We would also be scratching out heads. Yes sure we would work it out but also sure we would if we could ask questions which to those who know it all would I am sure seem silly.

That's a very different matter from

"Do I need to install one socket (fridge) per 13A fuse or I can install several sockets on one circuit?

What s the regulations for this?"

 

[ericmark]

You are assuming he is British what if he is like the name suggests from a French speaking country like Algeria where they used when I lived there three phase 110v phase neutral and 190v phase to phase. OK this was Algiers in 1981 and things may have changed.

 

[ban-all-sheds]

Even more reason why he should not be doing work like this until he knows more about it.