Author Topic: Voltage drop under load  (Read 18189 times)

Barenburg

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Re: Voltage drop under load
« Reply #15 on: September 25, 2018, 08:10:51 PM »
That clearly depends on the definition of need.

1. Need to make it Fool Proof?  yes
2. Need to meet code? probably
3. Need it to work correctly when tended by a competent person?  no

guest23837

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Re: Voltage drop under load
« Reply #16 on: September 25, 2018, 08:49:16 PM »
That clearly depends on the definition of need.

1. Need to make it Fool Proof?  yes
2. Need to meet code? probably
3. Need it to work correctly when tended by a competent person?  no

I was reading somewhere that you shouldn't backfeed power with the breaker switched to off? I am allegedly the competent person however I like to do things as well as I can. The guys on here know that I know very little about electricity and I no nothing of the code in Ireland the chap that did the wiring for me is a qualified electrician. I only recently got the generator on electric start it's now connected to a solar charger so battery will always be charged. I'd just use the pull start but I'd like it easy for the missus. If she forgot to throw the breaker....

guest23837

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Re: Voltage drop under load
« Reply #17 on: September 26, 2018, 08:30:23 AM »
So my system is ok apart from the changeover switch I need in case the wife plugs in the generator without throwing the breaker?

I did a little research and made a few calls yesterday. In order to fit the changeover switch you have to remove the main fuse coming into the house. This fuse has a lead seal on it so you have to notify the electricity company that you broke the seal so they can come out to re seal it and inspect the work. A qualified electrician cannot do this unless he is registered as well as he has to sign off on the job.  This is part of the code so retired electricians can't do this job as  obviously they forget a lifetimes work the first day the collect their pension.

A 125 amp switch is only about £40 so I will order one this week. The cable leading from the generator to the changeover switch has to be 20 square (wtf does that mean?) and it has to be installed "properly" which I assume means attached to the walls or buried underground? I have a feeling all this is going to be very expensive.

ajaffa1

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Re: Voltage drop under load
« Reply #18 on: September 26, 2018, 12:08:36 PM »
Hey Johndoh, yes a cross over switch is the way to go, not expensive nor difficult to wire up. you can legally do all the work yourself except for rerouting the incoming mains supply. I wired dozens of houses in the UK and just paid an electrician to test it and connect it. Cost for testing/connection was about £300. For what you are doing probably £100. Not too drastic and you get a certificate confirming compliance in the unlikely event that something goes wrong. Probably a good idea to send a copy to your insurance company so they can`t wriggle out of their responsibilities should something bad happen.

Bob

guest23837

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Re: Voltage drop under load
« Reply #19 on: September 26, 2018, 08:08:30 PM »
The yard is concrete so the cable will have to go inside a conduit under the eaves, I like Glort's control panel idea but really simplicity is all I want a few lights tv etc. I dont have many visitors they want my good coffee, the same bastards that give me weak instant coffee, they want to borrow stuff (I refuse). I will put it all in the hands of a spark that's still registered and I'll be covered. I kinda miss the little Kohler petrol generator and the exntention lead with 2 sockets, TV and a standard lamp.

ajaffa1

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Re: Voltage drop under load
« Reply #20 on: September 27, 2018, 09:42:52 AM »
Hey Johndoh, don`t pay a sparky to fit conduit and pull cable. Doing that bit yourself will save you a fair bit of money. Just let him do the clever bits at each end. I expect he is probably getting a considerable trade discount on cable and conduit, ask him to drop off the gear and tell him you`ll call him when you`ve done the donkey work.

Bob

guest23837

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Re: Voltage drop under load
« Reply #21 on: September 27, 2018, 09:53:24 AM »
Hi Bob

I saw on a different forum that you need to have the spark modify the cable you plug into the generator but it didn't say how why etc? Something to do with earthing it. The generator is earthed to 4 x 1m iron rods each about 2m apart.

thx Paul

ajaffa1

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Re: Voltage drop under load
« Reply #22 on: September 27, 2018, 12:43:30 PM »
Hi Paul, not sure about the earthing issue. Here in Australia the regulations are a bit different but I still like to go with what I used to do in the UK. I have one ST2 7.5 KVA generator, It has it`s own earth stake connected to the Generator head then the top box and then cross bonded to the engine and fuel tank.

There is an original Lister SOM control box in the shed, this has three 6 mm squared wires feeding it, two for AC current and one for earth.

I have a distribution board connected to the output from this setup. It has it`s own earth stake which is also connected with 6 mm cable to the control box.

From there the (6 mm) 2 live/neutral cables and earth cables run underground to the house distribution board where they link up with a cross over switch and another earth stake which is bonded to the previous two.

From there I have a feed going back to the shed to provide lighting/power etc. I have another distribution board with another earth stake.

So to make this as simple as I can: the generator requires connection to an earth stake with any parts separated by non conductive materials cross bonded. All distribution boards should have their own earth stake. All earth stakes should be connected to one another through the earthing bars in the distribution boards.

I strongly recommend that you water the area around the earth stakes prior to any testing by the local electricity authority if the weather has been dry for more than a week or two.

Bob

guest23837

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Re: Voltage drop under load
« Reply #23 on: October 09, 2018, 03:20:27 PM »
I had another spark out to do a quote. He told me 16 square cable would be fine for what I want. He said he would have to do tests on the negative wiring before he could do a quote. No clue what he means there. He thinks the backfeed I currently have would be fine reckons the less the state knows about what you do the better! He also suggested I dispose of that "dirty, noisy fcuking thing" and just use a small petrol inverter generator with a cable through the window for tv and lights. He's full of ideas anyway

BruceM

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Re: Voltage drop under load
« Reply #24 on: October 09, 2018, 06:53:46 PM »
Electricians vary greatly and in many states and countries have almost no technical training to speak of.  In my state not even a HS diploma is required.  Some have completed their apprenticeship managing to learn almost nothing.  Others with interest and aptitude may be much more knowledgeable on power hookups than the typical engineer.

There is no such thing as negative household wiring.  Perhaps he said neutral and you heard negative.

guest23837

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Re: Voltage drop under load
« Reply #25 on: October 09, 2018, 09:48:21 PM »
Electricians vary greatly and in many states and countries have almost no technical training to speak of.  In my state not even a HS diploma is required.  Some have completed their apprenticeship managing to learn almost nothing.  Others with interest and aptitude may be much more knowledgeable on power hookups than the typical engineer.

There is no such thing as negative household wiring.  Perhaps he said neutral and you heard negative.

Could be neutral he spoke quite fast and there was a lot of expletives! He is a registered qualified spark, he has to be to sign off on the work and he has to break the seal on the main fuse to do the work. That's illegal here in Ireland unless youre registered etc, I'm sure people have done it but I try to stay on the + side of the law however thin the margin is. It might be down to me if he was a chancer.

guest23837

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Re: Voltage drop under load
« Reply #26 on: October 10, 2018, 08:39:13 AM »
Glort I think he meant that power outages are usually short lived in Ireland and they don't happen all that often. The state here is very hands on as in hands on wallets, they want a cut of everything earned and an annual "inspection fee" for everything else. A friend built a house 15 years ago and the wiring for the generator was installed during construction. This was during the celtic tiger era when construction standards were self certified by the builder and there were no government inspections so in his case they don't know that it's been done.

Another quote might be a plan as #2 spark wasn't cheap although he does seem to know what he's doing. Can anyone explain (in laymans terms) about the issue with the neutral wires? Is it an extra money thing for the spark? 

ajaffa1

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Re: Voltage drop under load
« Reply #27 on: October 10, 2018, 09:50:12 AM »
Hi Johndoh, I think I understand what your sparky is concerned about. The grid system in Europe works with a neutral wire that you can safely touch without getting electrocuted. The positive/live wire goes from about +350 volts to -350 volts giving 240 volt RMS. If you touch this wire you will probably die.

Depending on the generator you have and how it is configured you could have a system in which the positive wire goes to +350 volt and then the negative wire goes to - 350 volt, still 240 volt RMS, but any piece of equipment in your house that has been earthed to neutral (a very common practice in modern electrical consumables) will become live and kill you.

Bob

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Re: Voltage drop under load
« Reply #28 on: October 10, 2018, 10:30:33 AM »
Hi Bob
Thanks for the info I understand about 25% of it. So could my house be unsafe backfeeding? Is there a way to fix this problem if I have it?
Paul

ajaffa1

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Re: Voltage drop under load
« Reply #29 on: October 10, 2018, 11:25:01 AM »
Hi Guy, there is a very simple way to check, Fire it up and then put a volt meter between the neutral and the earth, anything more than a couple of volts and you have a problem.

Yes wiring between two phases could cause this. Had a similar problem in UK hospitals years ago where they had three phase power. somehow they managed to split the phases so you had one phase on one side of a corridor and another on the other side of the same corridor. A whole load of cleaners got hurt using powered floor polishers, they were fine until they bumped the polishers into one another and then all hell broke loose.

Bob