Transformer or not

[Adamjamma]

Ok, I need to try to learn something better, and it is all due to the fact I am getting like ten different answers...lol...

if you have a 240/120 system... and want to use it for UK gear, I have been told I need a step up transformer by one source... that I can just hook it up by another source, and I need a buckboost transformer by a third source, so I can have different circuits fed by the mains...
have also received a warning from two manufacturers of certain equipment companies to not wire it as a usa 240 because it is designed for single live wire only... and will fail prematurely if wired by two live wires and no neutral... one of the equipment that I am dealing with is protected by an RCD and they have stated that I will have massive failures due to tripping if it is used on a USA style 240 circuit.

so...not too sure what method will use but need to start figuring it out... currently looking at a UK solar system just for the UK gear...

but is there a transformer method that can be employed that will give me the 120/240 of the local systems, and give me the 240 UK as well? The local frequency where this is going is not a problem as it is already 50 Hz.

the tools I plan on using, while available in US voltages in some cases, are paid for and cost sometimes eight times the cost in US voltages..lol

 

[gadfly56]

Ok, I need to try to learn something better, and it is all due to the fact I am getting like ten different answers...lol...

if you have a 240/120 system... and want to use it for UK gear, I have been told I need a step up transformer by one source... that I can just hook it up by another source, and I need a buckboost transformer by a third source, so I can have different circuits fed by the mains...
have also received a warning from two manufacturers of certain equipment companies to not wire it as a usa 240 because it is designed for single live wire only... and will fail prematurely if wired by two live wires and no neutral... one of the equipment that I am dealing with is protected by an RCD and they have stated that I will have massive failures due to tripping if it is used on a USA style 240 circuit.

so...not too sure what method will use but need to start figuring it out... currently looking at a UK solar system just for the UK gear...

but is there a transformer method that can be employed that will give me the 120/240 of the local systems, and give me the 240 UK as well? The local frequency where this is going is not a problem as it is already 50 Hz.

the tools I plan on using, while available in US voltages in some cases, are paid for and cost sometimes eight times the cost in US voltages..lol

Our resident Brits, Tony and Besoeker are probably your best source, but I definitely wouldn't try to run them on US configured 240 with two hots if they are designed for one hot and a neutral. I think you'll need a dedicated transformer for those tools.

 

[beanland]

415V 3-phase

415V 3-phase

I believe that UK voltages are 240V line-ground, 415V line-line 3-phase 50Hz. This means one of the 240V wires is at earth. In the USA, the voltage is 120V line-ground, 240V line-line for single-phase and 208V line-line for 3-phase, 60Hz. Both of the 240V wires are 120V above earth. Best bet is use an isolating transformer.

 

[jaggedben]

This is in Jamaica?

The truth could vary depending on details but here are my best guesses...

if you have a 240/120 system... and want to use it for UK gear, I have been told I need a step up transformer by one source...

Step up make no sense. Isolation or grounding transformer, maybe.

that I can just hook it up...,

If it is a really simple apparatus such as a 240V heater with just an heating element and rheostat, you can probably just hook it up to the two hot legs.

and I need a buckboost transformer ...

A buck boost (in buck mode) might be called for if you are running 230V equipment on a 240V system. But only if you are really concerned that the real voltage on the 240V nominal system would go more than 10% above 230V, i.e. above 253V. This could happen. But isn't 'UK equipment' still supposed to be rated for 240V nominal? I only know what Google tells me.

have also received a warning from two manufacturers of certain equipment companies to not wire it as a usa 240 because it is designed for single live wire only...

Potentially there's a safety issue with the equipment if some part of the equipment design assumes that one conductor is grounded. Probably there is one group of equipment that would be fine, another ground that would fully function but carry a potential safety hazard, and possibly another group that might shock someone or trip a breaker because neutral is bonded to the frame. It's the second and third group that should worry you and it's why people are telling you to use an isolation transformer.

and will fail prematurely if wired by two live wires and no neutral...

I highly doubt that two live wires will cause 'premature' failure. See previous comment. Running 230V rated equipment on a 240V nominal system could possibly do that though.

one of the equipment that I am dealing with is protected by an RCD and they have stated that I will have massive failures due to tripping if it is used on a USA style 240 circuit.

Seems somewhat doubtful to me, but I hesitate to draw conclusions without more complete knowledge of the equipment.

 

[Adamjamma]

The response I got from engineering at Schneider UK was the RCD or gfci would read the live leg on its neutral as too much current and trip... although he also said that all the 240 volt rcbo and McB breakers could be used on 120 volt circuits without problems and some of Schneider’s are actually UL listed...

 

[jaggedben]

The response I got from engineering at Schneider UK was the RCD or gfci would read the live leg on its neutral as too much current and trip... although he also said that all the 240 volt rcbo and McB breakers could be used on 120 volt circuits without problems and some of Schneider’s are actually UL listed...

Sounds like either nonsense or an inaccurate explanation. The current on the 2nd leg should be the same in both situations. Now if the protective device somehow expects a certain voltage relationship between neutral and ground then there could be an issue. I don't know enough about how those devices work to be 100% sure.

 

[GoldDigger]

If the RCD is built on the assumption that one current sense lead is in fact always a grounded conductor, there could be a problem using it on 120-0-120 instead of straight 240-0.
But a US two-pole GF detector should work just fine.
Just the opposite, a US device that counted on balanced leakage from two opposite polarity phases to satisfy a GFCI might trip an RCD when used on 240-0.

Sent from my XT1585 using Tapatalk

 

[LarryFine]

Sounds like the solution is a 240v-to-240v transformer with an end-grounded secondary.

 

[drcampbell]

If it's a small consumer, (less than 1.4 kVA or so) there are additional possibilities:

Plug it into a 120-volt receptacle and use a
120-240 step up transformer,
120-240 autotransformer, or
120-120 transformer wired for boost.
The second & third options have the advantage of needing only half as much transformer capacity.

Are British plugs polarized? It appears that a two-conductor plug could be plugged in either way.

 

[Tony S]

Sounds like the solution is a 240v-to-240v transformer with an end-grounded secondary.

That is the way I would go.

Are British plugs polarized? It appears that a two-conductor plug could be plugged in either way.

Yes

 

[Adamjamma]

That was my thought.. an end grounded where that is the neutral line... just was not sure of availability... still, should give least amount of losses and balancing problems for the rest of the system... now to find it at a reasonable cost..lol..

 

[Besoeker]

Are British plugs polarized? It appears that a two-conductor plug could be plugged in either way.

They are polarised and three pin. Live, neutral, and earth. They can plugged in only one way. They are rated at 13A and the live is fitted with a fuse.

https://www.google.co.uk/url?sa=i&r...aw1nCRFvjlXkmIJqLvc5XDGa&ust=1536490171055096

 

[drcampbell]

So there aren't any two-conductor, non-earthed plugs in the UK? Were there in the past?

 

[Besoeker]

So there aren't any two-conductor, non-earthed plugs in the UK? Were there in the past?

Isolated shaver sockets in bathrooms take two pin plugs. There was the one in hotel we stayed at a couple of weeks ago but who has a mains powered shaver these days?

 

[AdrianWint]

So there aren't any two-conductor, non-earthed plugs in the UK? Were there in the past?

In the past..... yes!

BS546 defined 2 pole plugs in ratings of 2A, 5A, 15A & 30A. All were to be found in domestic housing with the 5A being the most popular (and often connected to lighting circuits). It was usually installed to power the "wireless". The 15A would have been used to power a heater.

The two pole sockets were very quickly (1930s' I think) superseded by three pole versions. The pin sizes were the same as the two pole version, so a 2 pole 5A plug could be inserted into a 3 pole 5A socket. The earth pin was always bigger (actaully the same size as the L & N pins of the next size plug upwards).

However, the 13A 3 pin plug discussed above came along just after World War II and the other plugs started to be removed. I suspect most were removed through the 1970s & 80s. Very few, if any, 2 pole remain in use now.

The 15A three pin survives in theatre/entertainment (don't want a fuse in a plug up on a lighting rail!) & the 5A three pin is sometimes fitted in 'high end' domestic to allow a table lamp to be controlled with the room lights by a switch on the wall.