Electrics

[Oogyflip]

Hi all,

I am just about to purchase my first narrowboat. The boat has 12v lighting, but no electric sockets. It also has a stand alone inverter. Can someone give me a guesstimate as to how much it will cost to wire (by a professional) in sockets to run off the 12v and 240v via the inverter supply?

I hope that makes sense ?

Oogyflip

[Alan de Enfield]

I am guessing at the moment you have a small 'cigarette lighter' plug in one

 

You will need to decide what size inverter you need - Inverter prices vary between £60 and £1000 so will have a major impact on your 'quote'.

 

 

What do you want to power ?

What may you want to power in the future ?

 

There is a big difference in the size needed to run 'a TV and phone charger' to one needed to run a fridge or freezer, to one needed to run a Computer and an electric toaster or immersion heater, or deep-fat fryer, hairdryer etc etc.

 

You will also need to think about the size of your battery bank that will be needed to support the 'whatever sized' inverter, and consider your charging means to replace the electricity used.

 

Your electrics are a SYSTEM and is made up of many parts, just changing one part of the system can result in problems elsewhere, so everything needs to be considered.

Edited September 9, 2016 by Alan de Enfield

[Arthur Brown]

First you need to list the items that you need to run together and their wattage, then perhaps add a bit for expansion. Then you know your consumption. After that you must work out where that electricity will come from summer and winter.

 

It's a waste of money and decor to pull in wires that will be under size in the near future.

[Alan de Enfield]

First you need to list the items that you need to run together and their wattage, then perhaps add a bit for expansion. Then you know your consumption. After that you must work out where that electricity will come from summer and winter.

 

It's a waste of money and decor to pull in wires that will be under size in the near future.

 

There is a 'bit more to it' than that.

 

A fridge (for example) may have a wattage of 60 watts, however it may need 10x that to 'kick in', A microwave oven rated at 850w will actually draw more than 2x that.

 

Its no use thinking "I just want to run a 60w fridge - if I get a 300w inverter I'll have plenty of capacity"

 

It is no use looking at 'just the label' you need to know how the product works.

 

Edit to add :

The 850w quoted for a microwave oven is its 'output power' (the power going into the food), not the power it uses to run. (Roughly) a microwave usage is 2x that of its output.

Edited September 9, 2016 by Alan de Enfield

[Oogyflip]

The inverter on the boat is 600w. The boat has 2 leisure batteries, and I was thinking of adding 2 more? I may run a tv, tablet and possibly a few small things. I was gonna see how things go with the 600w inverter, and possibly get a larger one if needed in the future.

I'm just looking for a ball park figure of costs to run the wiring to add maybe 3 12v electric sockets. That can also be run from the inverter? I am right in thinking that the inverter converts the 12v system into 240v?

Please be gentle with me

Cheers

Oogyflip

[Alan de Enfield]

Sorry - more questions :

 

What type of inverter is it ?

 

Pure Sine wave (PSW), or Modified sine wave (MSW).

Some electronic items will not run off a MSW.

 

Do you have a 'mains hook-up' for battery charging ?

Are you looking to put a mains hook up whilst doing the rest of the circuit ?

 

How are you planning to charge your batteries ?

Are you liveaboard or leisure user ?

Are you CCing, In a Marina, 'wild mooring' ?

Are you planning on installing solar Power

Are you planning to use a generator ?

Have you got a battery charger ?

 

As I said before it really is a 'system' and you do need an understanding of 'whats what' to be able to ask the right questions - what is the size (Ah) of the two current batteries ? How old are they ? What is their current capacity ? Have you got room for two more ? Are you going to just add the two new ones to the two old ones ?

 

The usage of 'resources' on a boat (water, electricity, waste) is very different to being land based - in a house you just turn on a light and there is power - on a boat you firstly have to make it with your own 'power station' and then be very economical with it. There is a general misunderstanding about how much it takes to recharge a battery - typically (and every installation varies) the suggestion is commonly that you will need to run your engine / generator for 3+ hours every day and then maybe 8 hours at weekends.

 

If / when you go ahead make sure that it is all wired up so that an upgrade (larger inverter) can easily be accommodated without having to replace too much of the cabling. Oversizing the cable initially is far better than undersizing it.

[Bloomsberry]

I've got 2 leisure batteries and run a 1000w inverter and it copes ok. I only run high wattage appliances sparingly ie power tools, microwave so it doesn't drain the batteries too much.

 

I've used 1.5mm cable for the 240v as I also have 240 hook up at the marina so need the system to be capable of supplying 13amps max although the inverter won't get anywhere near this.

 

I think modern LCD TVs tend to take about 50-70 watts depending on size and a tablet is minimal so your 600w inverter will be more than enough to power these.

 

I don't use 12v for any portable appliances although I do have a 12v fridge - Edit

Edited September 9, 2016 by Bloomsberry

[Alan de Enfield]

 

To answer the last part of your question - yes an inverter takes 12v DC and converts it into 220v AC, it is not 100% efficient in the conversion and it actually uses power to just 'stand switched on doing nothing'

You will probably get something like 15%-20% losses.

 

As an example running a 1000 watt toaster will use about 4 amps from the mains, but will take 40amps from the batteries.

[Sir Nibble]

What you need is a basic consumer unit with rcd and mcbs and an afternoon's worth of wiring by any ordinary electrician. If the mcbs are rated to the inverter "surge" rating then you will be fine for what you want.

[FORTUNATA]

Be careful who wires your boat. A.C. Electricians know their trade but tend to use domestic regs on boats and house cable. There are very few marine qualified electricians because the only courses are few and far between. Your best bet would be an AC electrician who owns a boat too. Actually in my case I had to dismantle the entire electrical system and start again. The electrician had given no access to the inverter charger fuse which blew. That left me with no power and the inverter was cabled tight into a cupboard and to the isolator rotary switch. In the end I took the inverter out of the circuit as really I am not totally keen on them.

[Alan de Enfield]

Be careful who wires your boat. A.C. Electricians know their trade but tend to use domestic regs on boats and house cable. There are very few marine qualified electricians because the only courses are few and far between. Your best bet would be an AC electrician who owns a boat too. Actually in my case I had to dismantle the entire electrical system and start again. The electrician had given no access to the inverter charger fuse which blew. That left me with no power and the inverter was cabled tight into a cupboard and to the isolator rotary switch. In the end I took the inverter out of the circuit as really I am not totally keen on them.

 

Correct - you do not wire a boat with 'domestic' Twin & Earth cable but should use 'flexible' conductors.

Edited September 9, 2016 by Alan de Enfield

[nbfiresprite]

Iam wiring a 40ft narrowboat this weekend for AC including shore line. With two circuits (One for the charger and water heater with the other for sockets ). I be using the following

 

Consumer unit with RCD plus 2 MCB's (£25-£30)

Neon Iights x2 (One wired for Polarity Indicator other for power on)(£5)

20amp 4pole 2 way Rotary switch (wired so that the charger circuit is only live when switched to the shoreline) (£20)

Male Shoreline Socket (£8)

Galvanic Isolator (£60)

20m 2.5mm Arctic Blue cable (I always work on circuit breaker rating plus a 3rd when it comes to AC cabling) (£22 ebay)

3 x 13amp Double sockets plus boxs (£3 each upwards depending on the brand)

2 x DP Fused Switches plus boxes (Water heater and charger) (£8each)

Panel meter with Voltage, Amps, Watts and Kilowatt hours (£10 ebay) (Useful if you have no access to the meter on the shoreline)

175 amp Circuit breaker for 1000watt (1500 watt surge 30 min rating) Inverter (£12)

 

Total £192 for parts. To installed all this and test, I expect to take a full day (Normal hourly rate for a boatyard £35 to£45 per hour)

 

The cost of the inverter is not included, But a good one pure sine wave inverter is about £500 upwards for a 1000 watts.

Edited September 9, 2016 by nbfiresprite

[WotEver]

Iam wiring a 40ft narrowboat this weekend for AC including shore line. With two circuits (One for the charger and water heater with the other for sockets ). I be using the following...

 

I didn't see bootlace ferrules in that list. They only cost a few pence and make the terminations so much more secure.

 

Tony

[nbfiresprite]

 

I didn't see bootlace ferrules in that list. They only cost a few pence and make the terminations so much more secure.

 

Tony

I tend to put a dab of solder on the cable ends

[Geo]

I tend to put a dab of solder on the cable ends

 

I seem to remember that is not recommended because the solder & flux run up the wire and the wire becomes a solid mass and tends to break where the solder ends inside the cable insulation. Using ferrules the wire is crimped in the ferrule and is less likely to break because of vibration etc.

Edited September 9, 2016 by Geo

[WotEver]

 

I seem to remember that is not recommended because the solder & flux run up the wire and the wire becomes a solid mass and tends to break where the solder ends inside the cable insulation. Using ferrules the wire is crimped in the ferrule and is less likely to break because of vibration etc.

 

Nothing wrong with your memory, that is absolutely correct. The entry into a ferrule is progressive and therefore 'gentle' in nature.

[nbfiresprite]

 

I seem to remember that is not recommended because the solder & flux run up the wire and the wire becomes a solid mass and tends to break where the solder ends inside the cable insulation. Using ferrules the wire is crimped in the ferrule and is less likely to break because of vibration etc.

I only stick a dab on the very tip to act as a end stop. As for ferrules they can come loose or unattached through vibration.

[mross]

Crimping is OK if done with the correct tool which is designed to use a very high crushing force. Cored solders (flux within) can lead to corrosion in salty environments

[WotEver]

I only stick a dab on the very tip to act as a end stop. As for ferrules they can come loose or unattached through vibration.

Oh no they can't. Not if properly crimped. A crimp performs a cold weld and the only way to remove it is to cut the cable.

 

13A sockets, switches and light fittings are designed for solid cable and stranded gets chewed, broken and eventually loosens off. Ferrules only cost a few pence and seconds to crimp on but hey, it's your boat.

[nbfiresprite]

Oh no they can't. Not if properly crimped. A crimp performs a cold weld and the only way to remove it is to cut the cable.

 

13A sockets, switches and light fittings are designed for solid cable and stranded gets chewed, broken and eventually loosens off. Ferrules only cost a few pence and seconds to crimp on but hey, it's your boat.

Then we agree to disagree. You use your method and I use my own. As for the wiring in both my narrowboat and my yacht, either has had any problems since being installed years ago.

 

And one final point cold welds do fail.

Edited September 9, 2016 by nbfiresprite

[Geo]

I only stick a dab on the very tip to act as a end stop. As for ferrules they can come loose or unattached through vibration.

 

Can't agree with you if the ferrules are correctly crimped. If you are using the correct flux, solder and temperature and applying it to multi-stand cables you can't help but have solder and flux creeping up the cable by capillary action.

[GUMPY]

I only stick a dab on the very tip to act as a end stop. As for ferrules they can come loose or unattached through vibration.

If the terminal has a screw in it that bears down directly on the stranded cable then using your way it will break individual strands as you tighten it. If however you use a bootlace ferrule the pressure from the screw will be spread across many strands and they wont break.

Sorry but your way is wrong.

[Oogyflip]

Thank you all so much for the feedback!

At the moment the boat has a modified sine wave inverter. I lied, there is one electric socket running from the 600w inverter. I plan to run very little in the way of consumer goods. Charging a tablet, phone and possibly a tv. The fridge is hardwired in.

I have been quoted between £400 and £600 to have wiring and fitting for two electric sockets, RCD, and a 350w victron inverter running off two 110ah leisure batteries. I'm gonna then see how things go, as I may increase to 4 batteries.

And again many thanks!

Oogyflip

[WotEver]

I'm gonna then see how things go, as I may increase to 4 batteries.

 

Oogyflip

Don't make the (very common) mistake of thinking more batteries equals more power. It doesn't. It simply means more storage. You still have to generate what you use (plus around 20%).

 

Tony

[MtB]

 

And one final point cold welds do fail.

 

 

Never mind failing, I remain to be convinced 'cold welding' exists in the first place. Sounds like a term dreamed up by a sales and marketing department. I'd be interested in a matallurgist's views on the likelihood of copper wire genuinely welding itself to the crimp terminal just by being squeezed very hard.

 

If pressing two metal things hard together actually welds them, why do we bother with all that oxy-acetylene and arc welding?