# Maplins inverter



## bigfoot (May 16, 2005)

Just flagged this up today 3000w inverter may be worth a punt.
http://www.maplin.co.uk/Module.aspx?ModuleNo=226535&C=Newsletter&U=09P06-1&T=183123


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## Pudsey_Bear (Sep 25, 2008)

I'm just in the process of getting this >>>1100/2200watt Inverter <<<, the cables are going to be 35mm2, with 100 amp fuses.

You might want to do the calculations on what you'll need, there's more to it than price.

Kev.


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## Zebedee (Oct 3, 2007)

bigfoot said:


> Just flagged this up today 3000w inverter may be worth a punt.
> http://www.maplin.co.uk/Module.aspx?ModuleNo=226535&C=Newsletter&U=09P06-1&T=183123


How many batteries do you plan to carry Biggy? 8O

If you do the sums you may well go a bit lukewarm on the idea? :? :wink:

Dave


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## Pudsey_Bear (Sep 25, 2008)

You've done it again, :lol: :lol: :lol: :lol: 

Kev.


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## GEMMY (Jun 19, 2006)

At least no-one's asked where you can buy it from. :lol: :lol: :lol: 

tony


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## Pudsey_Bear (Sep 25, 2008)

only a matter of time. :twisted: :twisted: :twisted: 

kev.


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## Zebedee (Oct 3, 2007)

Kev????

Who is this bloke Kev? :? :lol: :lol: :lol:


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## 108717 (Dec 12, 2007)

Bigfoot
For that kind of money you might as well buy a bloody Generator!

What do you have in there that needs this kind of juice? And as others have hinted at, what kind of batteries do you have that can SUPPLY that kind of juice!


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## Jezport (Jun 19, 2008)

Totally useless, you would flatten any combination of batteries in minutes if you use it at high load.

Get a genny, or a smaller inverter or both.


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## olley (May 1, 2005)

Kev_n_Liz said:


> I'm just in the process of getting this >>>1100/2200watt Inverter <<<, the cables are going to be 35mm2, with 100 amp fuses.
> 
> You might want to do the calculations on what you'll need, there's more to it than price.
> 
> Kev.


Hi if it gets a 2200watt drain it will blow your 100amp fuses in a second, I would suggest 300amp fuses, and 40mm2 cable

Olley


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## Pudsey_Bear (Sep 25, 2008)

olley said:


> Kev_n_Liz said:
> 
> 
> > I'm just in the process of getting this >>>1100/2200watt Inverter <<<, the cables are going to be 35mm2, with 100 amp fuses.
> ...


Yeah just what we need another different opinion :lol: :lol: 
It's not a 2.2kw it'a 1.1kw with 2.2kw surge, it's all there if you bother to read it properly, which is the reason I posted the link for Bigfoot, and the fuse/cable rating is correct.

Kev.


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## hymerbeliever (May 8, 2009)

Remember Power Out = Power In (ignoring inverter losses)

If the power out is 1100w, then the power in is at least that which is 92 amps at 12 volts.

Most leisure batteries are ~85 ah and so will supply 85 amps for 1 hour, so at 92 amps you'll flatten your battery in just over an hour with a 1.1kw loading....and you'll overheat the battery and distort the plates at prolonged high currents.


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## olley (May 1, 2005)

Kev_n_Liz said:


> Yeah just what we need another different opinion :lol: :lol:
> It's not a 2.2kw it'a 1.1kw with 2.2kw surge, it's all there if you bother to read it properly, which is the reason I posted the link for Bigfoot, and the fuse/cable rating is correct.
> 
> Kev.


Kev a 2.2kv surge will blow a 100amp fuse, thats why I suggested a 300amp.

This from the REUK site: http://www.reuk.co.uk/Fuses-for-Power-Inverters.htm
However most 1,000 Watt rated inverters can supply 2,000 Watts for a short period (10 seconds typically) in order that appliances such as pumps which need a burst of high current to get started can be used. Within 10 seconds a standard 100 Amp fuse would have long since burnt out, and so a 200 Amp fuse would have to be used for such an inverter. BUT, specialist inverter fuses have two ratings - a continuous rating and a blow rating. With this type of fuse, a 100 Amp continuous rated fuse would be perfect.

They then suggest a "Mega Fuse" as a cheaper alternative.

A 125A Mega Fuse available in the UK for around £5.00. As with all Mega Fuses, the blow rating is double that of the continuous rating making them perfect for use with inverters. This 125 Amp fuse could easily be used with a 1,000 Watt rated inverter connected to a 12 Volt battery bank.

Olley


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## hymerbeliever (May 8, 2009)

Olly...I recognise your MH and Micra from Hurley over May Day...hope you got free nights like we did for the no water fiasco!


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## olley (May 1, 2005)

Hi HB not me, never been to Hurley. 

Olley


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## bigfoot (May 16, 2005)

Gentlemen and ladies.
I have no desire to purchase such an invertor,I received the notification from Maplins,and thought to pass it on in case anyone is interested. I have 2x110 batteries which is sufficient for my needs. I do not wish to receive Sky Sport inside the Artic circle nor cook a microwave dinner by Lake Gardia.
My years camping since a young boy and motorhoming with my parents have taught me proper stewardship of power and water. If I wanted all the comforts of home I would stay at home.


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## Zebedee (Oct 3, 2007)

bigfoot said:


> If I wanted all the comforts of home I would stay at home.


Says it all Biggy! 

Motorhomes, and lots of other things, are getting just too sophisticated.

Not that I really want to bring back the little rubber doughnut you had to stamp on to run the cold (and only) tap! 8O :lol: :lol:

And we thought that was brilliant when it first came out! :roll: 

Dave


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## Pudsey_Bear (Sep 25, 2008)

somebodies bus pass is showing.

:twisted: :twisted: :twisted: 

As for Olleys advice, after having looked a the link he gave it makes a lot of sense to go down the mega fuse route, it's a little more expensive, but a good Idea.

Thanks Olley (is that because you're a wise owl then)

Kev


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## barryd (May 9, 2008)

I have had Hank the Tank for a year now and I think we have learned a lot in that year and as we wild camp a lot have learnt the need to reserve battery power. What I am intrigued to know is what anyone would want a bloody great invertor for. What high powered devices would you want to power? Am I missing out on something here cos I cant think of anything we have missed that dont work of 12v.


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## Pudsey_Bear (Sep 25, 2008)

Just found some 100 amp mega fuses on Ebay £1.95 (item No = 250415786596)	just need to find 3 holders now.

Kev.


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## bigfoot (May 16, 2005)

"somebodies bus pass is showing".

Not me an other couple of years yet-if they are still issuing them!

I think mainly this inverter would be of more use to the marine community especially canal boat owners who have the capacity to install it and they could run the engine all day to power this device.


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## Pudsey_Bear (Sep 25, 2008)

I meant a certain someone with a spring in his step, he just afraid to come out of the closet though :rofl: nfire: 

Kev.


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## Pudsey_Bear (Sep 25, 2008)

Olley said:


> A 125A Mega Fuse available in the UK for around £5.00. As with all Mega Fuses, the blow rating is double that of the continuous rating making them perfect for use with inverters. This 125 Amp fuse could easily be used with a 1,000 Watt rated inverter connected to a 12 Volt battery bank.


Whilst I'm in no position to disagree with the above from Olley, it worries me that it seems it won't blow until it gets to 250amps, if I'm reading it correctly.

Kev.


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## clodhopper2006 (Aug 13, 2006)

olley said:


> Kev_n_Liz said:
> 
> 
> > Kev.
> ...


This is not the case. I can't find a specific time/current graph for the fuse I recomended to Kev on another thread but I've no reason to assume they are too different to similar fuses such as a BS88 for example. Now if you assume a 10 sec loading of 2200w this will give a current of 183A. The time/current graphs in BS7671 show the BS88 above would take 18 minutes 20 seconds to blow. Where do you get it to be a matter of seconds to trip Olley?
Yes you could use 40mm sq automotive cable rated at 300A but it may be overengineering the problem a little.

Bob


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## olley (May 1, 2005)

Hi Bob if the inverter does produce 2200watts for a short period, its likely to be drawing around 200amps or more not 183amps if you allow for around 90% inverter efficiency.

And thats based upon 12v from the batteries, under this sort of loading it may drop lower, with a possible increase in current draw. As for cable sizes, I always get the biggest to minimise voltage drop and for safety.

I have a sterling 1800watt inverter on the van, when I get home I will load it up and stick the clamp meter on it, an see what it draws. Sterling recommended and supplied a 300amp fuse for this model.

Olley


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## clodhopper2006 (Aug 13, 2006)

olley said:


> Hi Bob if the inverter does produce 2200watts for a short period, its likely to be drawing around 200amps or more not 183amps if you allow for around 90% inverter efficiency.
> 
> And thats based upon 12v from the batteries, under this sort of loading it may drop lower, with a possible increase in current draw. As for cable sizes, I always get the biggest to minimise voltage drop and for safety.
> 
> ...


Efficiency wouldn't make any difference to the current drawn, only in the output power would the effect be seen.
Even with 35mm sq the volt drop over 3m would only be ).69V Well within the 6% +- tolerances.
Also if the voltage were to rise you would still get 18 minutes. You have to go right up to 500A before you see tripping currents less than 10 sec

Bob


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## clodhopper2006 (Aug 13, 2006)

Kev_n_Liz said:


> Olley said:
> 
> 
> > A 125A Mega Fuse available in the UK for around £5.00. As with all Mega Fuses, the blow rating is double that of the continuous rating making them perfect for use with inverters. This 125 Amp fuse could easily be used with a 1,000 Watt rated inverter connected to a 12 Volt battery bank.
> ...


Kev, fuses have to be able to deal with normal spikes for one thing but the other thing is to remember the job of the fuse is to protect the cable not the appliance. Fuses are designed bearing in mind things such as type of load, prospective short circuit current etc. They will blow instantly in the event of a short circuit without harm coming to the cable. They will blow pretty quickly in the event of a damaging over current but maybe not at all for a sight increase in current.

Bob


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## olley (May 1, 2005)

clodhopper2006 said:


> Efficiency wouldn't make any difference to the current drawn, only in the output power would the effect be seen.
> Even with 35mm sq the volt drop over 3m would only be ).69V Well within the 6% +- tolerances.
> Also if the voltage were to rise you would still get 18 minutes. You have to go right up to 500A before you see tripping currents less than 10 sec
> 
> Bob


Bob, Watts are a measurement of power, so it its producing 2200watts the efficiency of the inverter would effect the current drawn.

Olley


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## clodhopper2006 (Aug 13, 2006)

olley said:


> clodhopper2006 said:
> 
> 
> > Efficiency wouldn't make any difference to the current drawn, only in the output power would the effect be seen.
> ...


Sorry no it doesn't

Output power = input power less losses. 2200w is the input power.

Just because an inverter says it is a 2200w inverter it doesn't mean you'll get 2200w out of it. You'll get 2200 less losses of say 20% giving you an output power of 1760w.

If the rated power was the output power you would not be able to calculate input current without knowing the efficiency. In industry this would make it impossible to calculate other things that inductive loads demand such as power factor correction etc


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## olley (May 1, 2005)

Bob this from their site:

"The power inverter's peak power output is 2200 Watts."

So the input would be more in the region of 2400watts.

Olley


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## clodhopper2006 (Aug 13, 2006)

olley said:


> Bob this from their site:
> 
> "The power inverter's peak power output is 2200 Watts."
> 
> ...


ok you have access to a statistic that I haven't 

where did you find that? I'm not doubting you but it's most unusual to rate a non resistive load by it's output power.

It still wont blow a 100A fuse for 18 minutes though and volt drop on 35mm2 cable is still just over half a volt over three meters.


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## olley (May 1, 2005)

Hi Bob, this is an item for domestic use so power factor isn't really a concern. The efficiency is claimed to be around 10-15% 

If you follow the link, then go to "more inverters" and scroll down to the 1100w inverter. I admit its all advertising blurb and may have little relationship to reality.

No argument that my cable sizes are on the generous side.  

Olley


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## Pudsey_Bear (Sep 25, 2008)

Hi Olley and Bob,

I wish I knew only a small percentage of what you guys have forgotten.

The situation right now is, the MH has 1 x 16mm2 and 1 x 20mm2 in place but with no terminals, this will be removed shortly.

The next step is to get some 40mm2 cable in 7 pieces 2 x negative and 5 x positive
3 for the Positive battery link so I can have a fuse adjacent to each battery in case of a cable shorting out on the chassis as it goes through the floor, and 2 for the inverter, again so I can have a fused link.

The cables is now ordered, they had no 35mm in stock, so we go with 40mm.

The fuses are on hold until I'm sure of getting the right ones, but according to my cable supplier, the 125 mega fuses will blow after about 0.4 seconds allowing the inverter to surge up to 2.2kw then dropping to it's normal max of 1.1kw, however I don't think I'll have too much loading on the inverter except a microwave.

I would rather spend a little extra to get a safer system in place, but do need to have the correct fuses, this is paramount 

I confess I find it confusing to say the least, and in that department it appears I'm not alone, as soon as we have the correct type and size of fuse I'll order them.

Kev.


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## olley (May 1, 2005)

Hi Kev, you need to know a lot to forget a lot, and as I haven't forgotten a lot............... :lol: 

40mm2 cable is rated around 300amps, and as its the cable the fuses are protecting,I would go for a fuse between 250-300amps.

Olley


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## Penquin (Oct 15, 2007)

Kev,

I have watched this thread and the previous one and seen the numerous discussions about the amount of power to be carried by the cables. I do not know the figures and would not pretend to offer anything other than a complete novice's opinion as regards the installation you are planning.

My concern comes from the thought about the amount of current you are considering conducting, even if it is ONLY 185 amps it is still a massive amount of electricity to be taking out.

I am sure you have thought it through but is it really essential to install such a system to power the toaster, microwave and so on that i believe you wish to use?

Surely it would be safer, and probably cheaper when the cost of replacement batteries is considered, to buy a generator if that equipment is essential? They can be bought secondhand or new and I would have thought would not have required cables of the order of 35mm or so. Such cables will be inflexible, heavy and potentially will get hot - as has been said by other posters.

Surely going without your morning toast is better than putting yourself through these discussions - various posters have hinted at the safety of the system due to the very high demand you are putting on it.

I just wonder if this is really essential? Or are you in danger of following an idea into areas where your own safety is going to be potentially put at risk?

This is not a criticism of your project, merely an outsider (with a background including science and safety) who just wishes to express concerns.

Dave


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## clodhopper2006 (Aug 13, 2006)

Kev if you use 300A 40mm2 cable you may as well use 250A megafuses

http://www.vehicle-wiring-products.eu/VWP-onlinestore/fuses/fuses.php

They' ll take care of the higher currents and look after your cables

Penguin there's no real safety concerns here as the high current is derived from 12v not mains. The worst case scenario is a loose connection but that would only result in a high resistance which would reduce the current to next to nothing and the voltage would disapear at the inverter. 
A short would blow the fuse - again safe. 
I'm inclined to agree with you though on the whys and wherefores of doing the job but Kev wants to so I'm happy to help.


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## Pudsey_Bear (Sep 25, 2008)

I don't take it as a criticism Dave in the least, You may have worded it differently if that was your purpose :lol: :lol: :lol: 

However, I think the reason this post is causing so much discussion is because I'm not a sparky, and can't afford to employ anyone to do the job for me.

There has been lots of discussion on these fori?? about the best this that or the other to use in the MH, but not where the power is coming from, we won't read very often about which inverter to get or which cable/fusing etc, because most people don't want to do it for themselves, they get it done and forget about it, until it goes wrong.

The only thing different about this thread is it's a discussion of how to do it right and there is a little differing in opinion, I'm not exactly going off into territory where this hasn't been done, and all can see I'm nor taking the safety aspect lightly in any way, the opposite, if I'm not 100% certain of anything I need to do I'll stop and not continue until I am, I may be a bit ignorant of the theory surrounding the links between 12v/230, but daft I ain't.

I'm sure there are one or two MH's out there running an inverter on domestic 2.5mm cable, (but not for long) based on the reasoning that, well I'm only using a microwave, and it's all I have in the house it'll be fine.

I'm not normally a cautious person, I take daft risks all the time, but I learned a healthy respect for messrs, Count Alessandro Giuseppe Antonio Anastasio Volta, James Watt and Andre Marie Ampere, when playing with a Scalextric kit as a kid and found out the wrong way to extend a mains cable, cellotape is not a bad conductor, it didn't half make me vibrate.

Kev.

PS I should add that I'm grateful for all the posts on this even the ones which are a criticism of what I want to do, it all helps with the discussion, and when others search for how to do all this they will find some very helpful advice from some very intelligent people, on the correct way to fit it all.


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## Penquin (Oct 15, 2007)

Thanks for the reassurance Kev,

glad to hear it and yes you are probably right about how some people do it with "whatever is to hand"  

Like you I had minor electric shocks as a boy - hence my healthy respect for all things electrical but it is good to see the reassurance from clodhopper too! MHF needs all it's active posters!  

You are right about the considerable amount of discussion - I only hope that if anyone else contemplates a similar project they also will seek the wisdom of those that know! (Which does not include me as I said!)

Thanks once again for the post.

Dave


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## olley (May 1, 2005)

Hi I have an 1800watt inverter, and I also have 5kva genny, but my reasons for having an inverter is really down to quietness. I don't like running the genny, its noisy, smelly and drinks petrol like a fish.

An inverter enables me to run the toaster, wife's hairdryer, kettle etc. late at night or early in the morning, without disturbing anyone else close to me.

Coupled with two large solar panels to recharge the batteries, I believe it is for me; an ideal system. 

Olley


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## Invicta (Feb 9, 2006)

I have had problems with the electrics on my RV ever since I first bought it new in January 2006.

I have at last found an electrician who appears to me to know what he is talking about. He at least has got the motor battery charging from the hook up which has never happened before as the battery only lasted about 2 weeks after returning home from a trip.

Two weekends ago I went to the Kent Country Fair at the Hop Farm at Paddock Wood near Maidstone (and very good it was too). After only 4 hours of running lights and electric door step, there was battery failure again. Running the generator for over 2 hours (in the corner of the field in daytime away from the rest of the M/Cs/RVs gathered for the show I will add), did nothing to put and power back into the batteries.

The electrician has always suspected that the inverter is at fault (1000 watt one is currently fitted). He has checked all three batteries and says they are OK. Before we set off for the non hook up Hamble rally on Friday he is coming to fit another inverter for me to try. The present one makes a whistling noise when the power has gone, in fact the first time it happened we were attending a rally of the motorcaravan section of the C&CC at Newark in May 2006. We were accused of running a generator all night by immediate neighbours; we must have slept soundly as we hadn't heard it!

I now recognise the sound and know to switch the inverter off when it happens. Can anyone tell me (of course I know someone soon will on here, such good value being a member for only £10!!!!) if this noise does indicate a faulty inverter?

As this will be my first MHF rally, are there any 'rules' about times for running generators in the event that the replacement inverter doesn't work?


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## Pudsey_Bear (Sep 25, 2008)

Our 300watt inverter made the same noise before it when to the little electrician in the sky, Looks a lot like a skip though.

Kev.


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## olley (May 1, 2005)

Invicta said:


> I .
> The present one makes a whistling noise when the power has gone, in fact the first time it happened we were attending a rally of the motorcaravan section of the C&CC at Newark in May 2006. We were accused of running a generator all night by immediate neighbours; we must have slept soundly as we hadn't heard it!
> 
> I now recognise the sound and know to switch the inverter off when it happens. Can anyone tell me (of course I know someone soon will on here, such good value being a member for only £10!!!!) if this noise does indicate a faulty inverter?
> ...


Hi some inverters have a low voltage alarm, so not only do they cut out if the battery voltage drops below a certain point, they also whistle or similar to let you know.

If your inverter is working ok to start with and its cutting out on low battery voltage, then its either U/S batteries or a fault in the charging system.

You need to check whether the coach batteries are being charged on EHU and by the alternator. Also batteries have a finite life, if over 5 years old I would suspect them.

Generally at shows/meets gennys are only allowed between 08.00-20.00

Olley


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## Pudsey_Bear (Sep 25, 2008)

clodhopper2006 said:


> Kev if you use 300A 40mm2 cable you may as well use 250A megafuses


Hi Bob, just looking for a little confirmation, as I'm a little confused here, I seem to remember that someone advised a 125 amp mega fuse, (can't find the post now) but you advise a 250amp megafuse, is this because of the increased ID of the 40mm cable, which is the only thing to have changed, and I realise that apart from the inverter, I'm only protecting the cables.

Watts divided by Volts = Amps 
max inverter output = *2200watts x 12volts = 183amps,* so my feeble old brain says anything between 183a up to 300a, will be OK, so was going to order 200amp MF's

Do I need to use the same fuse on the cable to inverter as on the inter battery cables

Kev.


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## Pudsey_Bear (Sep 25, 2008)

olley said:


> Generally at shows/meets gennys are only allowed between 08.00-20.00
> 
> Olley


I kept meaning to mention, that maybe one day we'll have to go onto a site, and we'd hate to be the only ones having to run a genny, because we didn't have inverter, also I hate the noise of our genny, and it's a fairly quiet one, and is one of the main reasons for fitting the inverter.

kev.


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## clodhopper2006 (Aug 13, 2006)

Kev_n_Liz said:


> clodhopper2006 said:
> 
> 
> > Kev if you use 300A 40mm2 cable you may as well use 250A megafuses
> ...


That's right Kev. so long as the rating of the fuse is less than the rating of the cable and above the rating of the appliance you can use any size in between. 40mm cable will allow you to plenty of leeway. By all means order 200A fuses they will be perfectly ok

Bob


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## Pudsey_Bear (Sep 25, 2008)

Cheers Bob, I thought for once I had an inkling of a clue for once.

I shall get them ordered today if I can.

Kev.

PS DURITE 200amp MEGA FUSE Ebay item code >>> (250415786584)

He's doing 3 x with holders all for £20.00 inc postage, I don't think I'll find them any cheaper.


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