Max power on single phase???

[Stump Grinder]

Does anyone know what the maximum amperage I am entitled to on a single phase supply? Are there published rules about this? Since new houses were built in our village our supply in much worse than before. I'm sure this has been covered before but cant find any thing.

 

[upnortheast]

I think ? the max off a single phase line is what they call a split phase supply which gives you 2 x 100 amp cables.
Unless anyone knows different ??
Your sparky should be able to test your supply
If you think new houses are affecting your supply you should complain ( every week at least) to your network operater (DNO ) After about 6 months of constant complaints they should put a monitoring box on the supply to see what is going on.

 

[Mur Huwcun]

Are you struggling for amparage or voltage? Can you find a sparky to test your incoming voltage at the meter? They have to supply a certain range. We were struggling at home due to a very old transformer. Electric motors would nearly stop when you arced the welder up and lights dimming in the other property that was on same transformer. Microwaves would not last very long and would nearly stop if you bolied kettle at same time!! In the end after the wind blew a supply line down the engineers on site put in a request for a new transformer. Everything is different now, light bulbs are lasting much longer etc.

Incidentally at our house when we re did everything it failed the electrical test due to an out of range earth reading. The electrician phoned scottish power up which visited that day and tested and put in a request for a new transformer and supply line. It’s not the same supply here now either, oven works better etc, kettle boils quicker and lights don’t dim. Get someone to test your supply

 

[Stump Grinder]

It is 100 amps per phase thanks for the replies. I think long term we need to reduce our power consumption at peak times we are getting fairly close to the max.

 

[Courier]

How are you using the power ?

For motors or heating ?

I used to run a 15hp 480 volt on floor grain drying fan from our 2 x 240 volt supplies

 

[Stump Grinder]

all motors on a dairy farm

 

[simon-0116]

Depends on supply fuse size and transformer / length of run/ bts drop from supplier

 

[TheTallGuy]

It is 100 amps per phase thanks for the replies. I think long term we need to reduce our power consumption at peak times we are getting fairly close to the max.

Typically it's 100A (23kVA)for a single phase domestic supply, although in some instances it will be lower due to being an older supply or low network capacity etc, usually the fuse at the service head will be your practical limit without significant upgrades. It is possible to request a greater than 100A single phase on a special project but the DNO is unlikely agree as it can make it difficult to balance usage across the phases in the local network. They prefer higher usage to be on three phase, which brings a requirement for the installation to minimise phase imbalance. A standard 3 phase supply will be 100A per phase, so 69k
VA, larger supplies are available but will cost significant wonga to pay for network capacity etc.

 

[Richard98]

Grandad had a similar problem 50 odd years ago, installed electric grain driers and when he dropped the motors into gear, the lights in the village would nearly go out?whoever ran the network back then put us a separate supply in from another way and 3 phase to boot, separate from the village. The lines are still in place from the village so last year when a pole broke on the news line, they swapped the fuses over and we were put on the old supply while they changed the pole. I dread to think what a separate supply would cost nowadays.

 

[arcobob]

As I recall the standard basic domestic supply in France was about 6KVA or 25 amps . Turn on the oven or an electric shower and the trip was likely to blow. In the UK single phase supply is a lot better but the start up amps on an induction motor are three to four times the run amps. Start the motor under load and the draw multiplies, Domestic refrigeration is a case in point,the Electrolux/absorbtion system has no compressor or motor and does not produce demand surges as does the normal system using a compressor. Big draw appliances include pressure washers, some lawnmowers, deep freezers and workshop compressors. Welders also produce demand spikes but for a different reason.