Load Balancing in a shop

[Chris]

Hi all,

A friend of mine who owns a shop has asked me if I can do some load balancing on the three phase board in the shop.

In my career I have mostly done domestic and light commercial so three phase load balancing is something I havent yet carried out.

Am i right in thinking it is just a case of assessing what each phase is using and re arranging the DB to more evenly spread the load?

Or is there a lot more to it than that?

Any advice/feedback appreciated.

 

[Strima]

If you have a lot of single phase loads then good luck trying to get them balanced.

Do you have a clamp meter?

 

[Chris]

If you have a lot of single phase loads then good luck trying to get them balanced.

Do you have a clamp meter?

I have not been to the shop but it is your typical small supermarket with freezers/fridges/plenty of lighting and power circuits for the office equipment in the back.

Yes i have a clamp meter.

 

[Deleted member 105166]

On a DNO supply, a load balancing exercise tends to be triggered by the need to add additional loads/circuits and seeing whether moving some single phase loads between phases yields up sufficient capacity on an already well loaded board (as opposed to doing it for the benefit of the DNO)

I would start by understanding what the owner wants to ultimately achieve and taking some 15 minute measurements for a week to identify demand and trends. Allow for equipment such as Air Conditioning, that may not be in use in November, but would have been heavily used this June & July. Also a good opportunity to look at lighting arrangements and current & monetary savings to be yielded by taking the LED plunge.

 

[buzzlightyear]

Yes i have a clamp meter.

crack on then ,Mr Scott. where are you going to start first .

 

[Chris]

On a DNO supply, a load balancing exercise tends to be triggered by the need to add additional loads/circuits and seeing whether moving some single phase loads between phases yields up sufficient capacity on an already well loaded board (as opposed to doing it for the benefit of the DNO)

I would start by understanding what the owner wants to ultimately achieve and taking some 15 minute measurements for a week to identify demand and trends. Allow for equipment such as Air Conditioning, that may not be in use in November, but would have been heavily used this June & July. Also a good opportunity to look at lighting arrangements and current & monetary savings to be yielded by taking the LED plunge.

Very helpful information thanks, he is looking at upgrading the lighting to LED in the near future and would like a feed installing for a soon to own ice cream freezer. However at the minute he has just mentioned that he is aware the phases are unbalanced and would like this sorting before any more work carried out.

I will take a few measurements before moving any further with it.

Thank again!

 

[Chris]

crack on then ,Mr Scott. where are you going to start first .

At the kettle.

 

[static zap]

Check ages of freezers , some can be really thirsty antiques !

 

[Chris]

So is the way to go about it;

Writing down what circuits are on each phase and what appliances/accessories are on each circuit,

Then using my clamp meter taking readings at each appliance to see what they draw.
Then once I have this information re arrange the DB so that the loads are suitably split across each phase taking into account seasonal/time specific appliances/loads?

 

[telectrix]

So is the way to go about it;

Writing down what circuits are on each phase and what appliances/accessories are on each circuit,

Then using my clamp meter taking readings at each appliance to see what they draw.
Then once I have this information re arrange the DB so that the loads are suitably split across each phase taking into account seasonal/time specific appliances/loads?

sounds like a plan. might be an idea to first clamp each phase and see how far out of balance they are. .. might not bee too bad.

 

[Andy78]

First thing I would ask is how the owner has become aware of the imbalance. Is it from recent advice by another electrician, has a DNO fuse recently gone, or is it waffle from someone like a fridge mechanic ?

 

[Chris]

sounds like a plan. might be an idea to first clamp each phase and see how far out of balance they are. .. might not bee too bad.

Great, Thanks a lot for the help guys

 

[Chris]

First thing I would ask is how the owner has become aware of the imbalance. Is it from recent advice by another electrician, has a DNO fuse recently gone, or is it waffle from someone like a fridge mechanic ?

I am not sure on how he has became aware of it currently, he has had a dedicated electrician for quite a few years but he has recently passed. So I think it may have came from him but at the moment im not certain

 

[ruston]

Have a very good look around before you take it on .
Some of these 'mini supermarkets' harbour some really inventive installations.

 

[snowhead]

It's most likely from a Fridge guy.
"That single freezer keeps tripping because the phases are unbalanced"
Instead of, I've not looked to see if it's the defrost heater, that'd be too hard..
Yes, I worked around retail fridge engineers for 25 years.