Low voltage - less than 190v some days.

[JohnW2]

Just curious - what's with all the blank posts from Mod 11?

They were telling the OP to edit or remove the 'advertising' signature from his posts. As soon as he did that, all the mod's messages went blank.

Kind Regards, John

 

[JohnW2]

If a loop meter is not to hand, then two voltmeters (calibrated against each other) and simultaneous measurements synchronised by mobile phone may provide a useful indication.

That's true (as are all the things discussed by eric) if one wants to measure voltage drop. However, I'm not sure that's really needed. The important question is whether the DNO-supplied voltage at the origin is falling below the 'permitted' limits. If it's not, then the boat club's distribution wiring is clearly to blame. If is is, then the DNO presumably have to become involved - either they are simply not providing an adequate voltage (which would be for the DNO to rectify) or else the boat club is drawing current well in excess of the ('contracted') capability of the DNO's service. The latter, of course, could be a problem, and potentially very expensive to address.

It wouldn't surprise me if the whole installation wasn't running off a 40A DP ironclad cutout in a shed somewhere

As above, that would be one of my concerns. We're not told how many sockets/boats are involved - but if there are a lot of them, sometimes each drawing 'a few amps' simultaneously, that could easily seriously overload anything like a standard 'domestic'-type service.

Kind Regards, John

 

[ericmark]

Be it a boat or a caravan back in the 1980's sites and marinas started to provide electric huck-up and in the main it was just to charge the caravan or boat battery often 5 amp or even less.

As time has gone on the users have asked for more and more and rules and regulations have complicated matters with minimum requirements.

The boat however is different from the caravan one because of earthing and two as mains power is also required away from the marina.

Many boat owner I know as a result have large inverters and take the shore power just to a Class II battery charger as it kills two birds with one stone. It removes the need to connect an earth and it provides constant power what ever the marina provides.

My son's old marina used 4A MCB's to power the 16A sockets and when he wanted to install heavier cables the other marina users were not interested as 4A was ample to re-charge batteries.

Not so bad with narrow boats nearly all are steel but with salt water marinas you have aluminium hulls and the owners are normally well aware of the problems with sharing an earth with a steel hulled boat or even worse a copper coated earth rod.

Use of isolation transformers also often means tapping so they can use 110, 120, 220, 230, 240 volt supplies and again it's a I'm all right jack I can move my tapping why should I pay for new supply to some boat who is doing it on the cheap with a diode rather than isolation transformer.

Although my son was living on a shoe string at the time many of his neighbours were rolling in money and had every mod con on the boat including inverter generators on the main engine.

For me as a industrial electrician with some domestic knowledge it was an eye opener. I just could not believe anyone would pay so much for a Wispergen but clearly when they had they were not inclined to accept noise from a neighbours generator. Until then I thought a sterling engine was a kids toy.

 

[ban-all-sheds]

They were telling the OP to edit or remove the 'advertising' signature from his posts. As soon as he did that, all the mod's messages went blank.

Bad Matty!

He's been a member long enough to know he mustn't do that

 

[mattysupra]

So we start with 230 v +10/-6% = 253 - 216.2 volt at the DNO head for power you are allowed a further 5% and lighting a further 3% so 205.39 or 209.714 depending if power or lighting supply. I seem to remember there are some time limits as well.

So in real terms an appliance should work at 205 - 253 volt if it does not work at 205 then down to appliance not the supply.

The volt drop is simple ohms law so 6mm² cable for example will have a volt drop of 7.3 mV/A/m so a 100 meter run with 10 amp draw will give a volt drop of 7.3 volts.

However the problem is to measure volt drop as walking from one end of the marina to other to take two readings it may have changed anyway so the way to measure is with a loop impedance meter.

These meters have a built in load and by measuring the voltage with and without the load will give an impedance reading directly from the meter. So starting at as close to the DNO supply you take a reading. This tells you the value in ohms of both the cable and the transformer. Typical in a house would be 0.35Ω.

Next is a clamp-on ammeter which will show how much you are drawing so as an example lets say 100A.

Now if the DNO was to set the tapping to give 253 volt no load then simple ohms law you would get 218 volt at the head.

The same method can be used at each outlet to work out what the volt drop should be if no one is cheating.

Step one is to find if the major part of the problem is supply or internal wiring and using a loop impedance meter you can work that out. Clearly if a supply problem then down to talks to DNO. I remember at a factory having talks about increased power requirements and it was about either a second transformer or a larger transformer and we were not charged by the kWh but by maximum demand at set parts of the day. So much would depend on the agreement signed by the club.

If it is volt drop within the club then it needs some careful planning a radial supply could be made into a ring for example by simply running a new cable to the end of the radial.

It may be curable by an agreement which boat cooks at what time.

I was reading on a boating forum about inverters designed to top up top requirements so a boat could have a 4 amp supply and the inverter can supply the extra 6 amp at peak times.

Likely there will be some cost and what the members have to decide is how best to spend their money. May be solar panels are the answer with the grid tie inverter this would clearly boost voltage during the day and reduce bills.

Warning grid tie inverters have safeties to stop them boosting the voltage to over 253 volts and also to switch off when there is a power failure. There will be a lower voltage limit as well as the upper one and once the inverter trips it remains off line for a set time the idea is with a road full of inverters if the supply is removed the inverters will not just sense each other so continue running but will close down likely one at a time and I am not sure of the points where they close down.

Thankyou for your indepth post, Will need to read it a few times for it to sink in, but many thanks.

 

[mattysupra]

They were telling the OP to edit or remove the 'advertising' signature from his posts. As soon as he did that, all the mod's messages went blank.

Bad Matty!

He's been a member long enough to know he mustn't do that

Yep my error, member for a long time. However a few years ago I wrote a few stickies and asked if I could have a sig link as many people kept questioning my replies and that if they knew who I was (in the flooring trade) then it might help the questions being asked.

Another member who owned a shop moaned so I removed my link to keep the other member happy. As the other member does not use this forum any more and with someone asking the question "does anyone know the answer" on a post I replied to regarding the questions I asked I decided to put sig back up.

The sig was not intended to advertise , simply to give a heads up to the person asking a flooring question. My company / training centre is Europe's largest and apparently the worlds largest so I defo have no need to advertise .

Anyway, the mods (new mods I guess) was not to know previous agreements so I simply removed. Job done.

Naughty boy ? ye I guess reading the rules but not the same rules as agreed years ago

Anyway,