Isolating Transformer.

[Phoenix_V]

25 minutes ago, sailor0500 said:

 "Old Goat" in post nine who recons one is not needed at all.

you will find several threads on that subject

[WotEver]

1 hour ago, sailor0500 said:

Agreed. But then even that was contradicted  by "Old Goat" in post nine who recons one is not needed at all.

Yes, but as that wasn’t your question I’d say you can ignore it

[Tony Brooks]

1 hour ago, sailor0500 said:

Agreed. But then even that was contradicted  by "Old Goat" in post nine who recons one is not needed at all.

First of all I read post 9 as asking why one was needed not stating one is not needed.

 

Secondly you really need to assess each poster's expertise in the subject area. I have seen little to suggest that in electrical topics Old Goat knows more than Wotever and others who have provided good quality discussion. It is by discusson that we all learn.

 

FWIW I too say Airlink is the IT usually recommended especially after,as I understand it, Victron (I think)  ones were found to be wrongly wired.

 

My view on the subject is that some form of "mains earth wire" isolation is required but if it is to be an IT or GI depends on the use it will get put to and if one can afford an IT. For example if you just popped into marinas now and again and used the shoreline overnight a GI with status indication is likely to be sufficient but if you were on a shoreline 24/7/365 then an IT may be a safer bet.

[sailor0500]

On 01/10/2020 at 16:58, Tony Brooks said:

First of all I read post 9 as asking why one was needed not stating one is not needed.

 

Secondly you really need to assess each poster's expertise in the subject area. I have seen little to suggest that in electrical topics Old Goat knows more than Wotever and others who have provided good quality discussion. It is by discusson that we all learn.

 

FWIW I too say Airlink is the IT usually recommended especially after,as I understand it, Victron (I think)  ones were found to be wrongly wired.

 

My view on the subject is that some form of "mains earth wire" isolation is required but if it is to be an IT or GI depends on the use it will get put to and if one can afford an IT. For example if you just popped into marinas now and again and used the shoreline overnight a GI with status indication is likely to be sufficient but if you were on a shoreline 24/7/365 then an IT may be a safer bet.

Sorry if my tongue in cheek comment about being more confused caused offence. It was only intended to show how confusing discusion can be to those with no expertse in the subject. As I use marina supply 24/7 I think I will go with an Isolation transformer but get rid of the electric kettle which if I read the posts correctly a 1500Kva should suffice.

[Phoenix_V]

you can get low wattage kettles https://www.amazon.co.uk/KINGAVON-Cordless-Kettle-Litre-White/dp/B004NO873Q/ref=sr_1_4?dchild=1&keywords=small%2B1000w%2Bkettle%2Belectric%2Bcordless&qid=1601728227&sr=8-4&th=1

 

what else are you using

[sailor0500]

2 minutes ago, Phoenix_V said:

you can get low wattage kettles https://www.amazon.co.uk/KINGAVON-Cordless-Kettle-Litre-White/dp/B004NO873Q/ref=sr_1_4?dchild=1&keywords=small%2B1000w%2Bkettle%2Belectric%2Bcordless&qid=1601728227&sr=8-4&th=1

 

what else are you using

Desktop computer, reading lamp, 30amp Dc 4 step switch mode Sterling charger/powerpack.

[Phoenix_V]

8 minutes ago, sailor0500 said:

Desktop computer, reading lamp, 30amp Dc 4 step switch mode Sterling charger/powerpack.

That would be fine I would switch the charger off while using the low wattage kettle, do you not have an immersion heater?

[sailor0500]

13 minutes ago, Phoenix_V said:

That would be fine I would switch the charger off while using the low wattage kettle, do you not have an immersion heater?

Yes, I never thought about that as I don't use it. Always shower at the facilities block and use the kettle for washing up etc. Just looked and it is rated at 1kv 240v.

[Tony Brooks]

1 minute ago, sailor0500 said:

Yes, I never thought about that as I don't use it. Always shower at the facilities block and use the kettle for washing up etc. Just looked and it is rated at 1kv 240v.

Er probably 1 kW power, not 1000 volts.

[sailor0500]

1 minute ago, Tony Brooks said:

Er probably 1 kW power, not 1000 volts.

Yes. Slip of the tongue, or finger!

[Phoenix_V]

so the immersion OR kettle use 1kva (or 1kw)each so only one on at a time, leaves .5kva headroom for small bits

[Alan de Enfield]

50 minutes ago, sailor0500 said:

1500Kva should

Maybe an error in units ?

 

1,500,000 Va. you'd be needing VERY fat cables.

[sailor0500]

3 minutes ago, Alan de Enfield said:

Maybe an error in units ?

 

1,500,000 Va. you'd be needing VERY fat cables.

Yes.

9 minutes ago, Phoenix_V said:

so the immersion OR kettle use 1kva (or 1kw)each so only one on at a time, leaves .5kva headroom for small bits

Thanks for the advice.

[ditchcrawler]

3 hours ago, Phoenix_V said:

you can get low wattage kettles https://www.amazon.co.uk/KINGAVON-Cordless-Kettle-Litre-White/dp/B004NO873Q/ref=sr_1_4?dchild=1&keywords=small%2B1000w%2Bkettle%2Belectric%2Bcordless&qid=1601728227&sr=8-4&th=1

 

what else are you using

We have a similar one with a larger water capacity, running from a 1500 watt inverter

[cuthound]

4 hours ago, Alan de Enfield said:

Maybe an error in units ?

 

1,500,000 Va. you'd be needing VERY fat cables.

 

And a big boat to put it on?? (the image is of a 3 phase 11,000 volt to 433 volt HV transformer).

[ditchcrawler]

Just now, cuthound said:

 

And a big boat to put it on?? (the image is of a 3 phase 11,000 volt to 433 volt HV transformer).

It "should" be mounted on the shore, not the boat so everything on the boat including the plug and cable is not connected to the shore earth. So it will be fin. Does it cost less than an Airlink?

 

[cuthound]

11 minutes ago, ditchcrawler said:

It "should" be mounted on the shore, not the boat so everything on the boat including the plug and cable is not connected to the shore earth. So it will be fin. Does it cost less than an Airlink?

 

 

I know, but most marine ITs I have seen have been mounted inside the boat.

 

When I was last working, (2013), we used to allow £1 per kVA as a rough approximation for most power equipment (transformsrs, diesel generators,  UPSs etc, although copper price varied wildly over short periods ofvtime), so the one in the image would cost circa £15,000, plus 7 years inflation. 

[ditchcrawler]

1 hour ago, cuthound said:

 

I know, but most marine ITs I have seen have been mounted inside the boat.

 

When I was last working, (2013), we used to allow £1 per kVA as a rough approximation for most power equipment (transformsrs, diesel generators,  UPSs etc, although copper price varied wildly over short periods ofvtime), so the one in the image would cost circa £15,000, plus 7 years inflation. 

And as much again for National power to install it 

[sailor0500]

https://airlinktransformers.com/product/enclosed-isolating-industrial-transformer-wm2257

 

Just been looking at the airlink site and think this may fit my requirements, possibly with a soft start fitted as others have suggested. I would appreciate any constructive comments/ observations. Thanks Mike.

[WotEver]

11 hours ago, sailor0500 said:

https://airlinktransformers.com/product/enclosed-isolating-industrial-transformer-wm2257

 

Just been looking at the airlink site and think this may fit my requirements, possibly with a soft start fitted as others have suggested. I would appreciate any constructive comments/ observations. Thanks Mike.

Not waterproof, so it can't sit outside and it's metal, so the case must be earthed - a big problem in itself. 

Edited October 5, 2020 by WotEver

[Phoenix_V]

The

11 hours ago, sailor0500 said:

https://airlinktransformers.com/product/enclosed-isolating-industrial-transformer-wm2257

 

Just been looking at the airlink site and think this may fit my requirements, possibly with a soft start fitted as others have suggested. I would appreciate any constructive comments/ observations. Thanks Mike.

On 03/10/2020 at 16:36, ditchcrawler said:

 

The surge limiter will  act as a soft start. 2250 va will allow up to 2kw of heating (ie kettles immersion heaters room heaters at the same time (lower for motor devices) as long as you are happy that is enough

Edited October 5, 2020 by Phoenix_V

[GUMPY]

That is very similar to the one I have. For many years it resided in the shed where the supply is and was fine in its metal case, the case is earthed to the incoming supply as it should be.

When I moved it onto the boat (where it shouldn't really be) I had to re-case it as you cannot have a metal cased IT on a boat. Victron made this mistake and tried to rectify it by grounding the case and screen to the boat which provides no protection in the case of an incoming supply fault to ground.

If you intend to put the IT on the boat the best thing would be to put it in an HDPE box and get rid of the metal case. Putting it in a wooden box will not do as wood is a conductor especially when damp.

Also bin the thermistor that they supply as a soft start and fit something similar to the one I linked to earlier.

Edited October 5, 2020 by Loddon

[cuthound]

22 minutes ago, Phoenix_V said:

The

The surge limiter will  act as a soft start. 2250 kva will allow up to 2kw of heating (ie kettles immersion heaters room heaters at the same time (lower for motor devices) as long as you are happy that is enough

 

I think you mean VA not kVA.

 

A 2250kVA tranformer will allow up to 2 Megawatts of heating and be even bigger than the one in the photo of post #65. ?

[Phoenix_V]

36 minutes ago, cuthound said:

 

I think you mean VA not kVA.

 

yes

[Phoenix_V]

1 hour ago, Loddon said:

That is very similar to the one I have. For many years it resided in the shed where the supply is and was fine in its metal case, the case is earthed to the incoming supply as it should be.

When I moved it onto the boat (where it shouldn't really be) I had to re-case it as you cannot have a metal cased IT on a boat. Victron made this mistake and tried to rectify it by grounding the case and screen to the boat which provides no protection in the case of an incoming supply fault to ground.

If you intend to put the IT on the boat the best thing would be to put it in an HDPE box and get rid of the metal case. Putting it in a wooden box will not do as wood is a conductor especially when damp.

Also bin the thermistor that they supply as a soft start and fit something similar to the one I linked to earlier.

Ah I knew there was a reason why I didn't buy the ready boxed version! They sell the transformer circuit board and surge limiter separately if you search the website or just phone them and ask, my experience is the surge limiter is OK but I would uprate it (in fact I uprated everything including the transformer). I built a box out of fireproof board, allowing space to dissipate heat with ventilation holes fitted with fireproof mesh and a precautionary thermal cut out so it all got a bit complicated but I wasn't going to trust the potted version again and it still cost less.