240v wiring

[Cloudinspector]

I'm currently converting a 30ft butty into a workshop for my wife to use as a stained glass studio. I'll be installing a shoreline inlet for use with a generator. This will power a battery charger and some sockets. There's also an inverter already fitted along with the charger which is fed from two 100ah batteries. 

Here's the wiring diagram I intend to install. Can the clever folks on here tell me if it's correct please.

 

Edited April 26, 2017 by Cloudinspector
Trying to add image

[rusty69]

2 minutes ago, Cloudinspector said:

 Can the clever folks on here tell me if it's correct please.

 

%5BURL=http://s1334.photobucket.com/user/cloudinspector66/media/IMG_0339_zpss26v4vfs.jpg.html%5D%5BIMG%5Dhttp://i1334.photobucket.com/albums/w658/cloudinspector66/IMG_0339_zpss26v4vfs.jpg%5B/IMG%5D%5B/URL%5D 

I'm not clever enough to get the link working. 

[Cloudinspector]

10 minutes ago, rusty69 said:

I'm not clever enough to get the link working. 

Image should be there now.

[WotEver]

7 hours ago, Cloudinspector said:

I'm currently converting a 30ft butty into a workshop for my wife to use as a stained glass studio. I'll be installing a shoreline inlet for use with a generator. This will power a battery charger and some sockets. There's also an inverter already fitted along with the charger which is fed from two 100ah batteries. 

Here's the wiring diagram I intend to install. Can the clever folks on here tell me if it's correct please.

You don't show the charger. That should be fed from the shore power inlet before the change-over switch. 

[Jen-in-Wellies]

I am not a sparky, but a couple of things. You should have an rcd just before the mcb, or a combined rcbo to protect people on the boat, or nearby if there is a live to earth fault. Also, there isn't a galvanic isolator, or isolation transformer between the shore socket and changeover switch. Probably fine if it is only ever used connected to a generator, but you can't ever be tempted to connect it to a shore bollard, or any slight difference between bollard earth voltage and the boat could lead to galvanic corrosion of the hull.

Any proper boat sparkies around?

Jen

[WotEver]

As the butty is only ever going to be externally powered from a genny there is no need for an IT or GI. 

If both the genny and inverter have a floating output then an RCD would achieve nothing, however if they can both be N-E linked then it would be a good idea to do so and add an RCD as an extra layer of protection. 

[Cloudinspector]

1 hour ago, WotEver said:

You don't show the charger. That should be fed from the shore power inlet before the change-over switch. 

The charger was fitted before we bought the butty and has a 3 pin plug. My idea was to fit a socket and switch it on when using the generator.  It hasn't crossed my mind to wire it before the change over switch.

[WotEver]

39 minutes ago, Cloudinspector said:

The charger was fitted before we bought the butty and has a 3 pin plug. My idea was to fit a socket and switch it on when using the generator.  It hasn't crossed my mind to wire it before the change over switch.

The danger of doing it 'your' way is that you might simply forget to unplug it when powering from the inverter. 

[Cloudinspector]

5 hours ago, WotEver said:

As the butty is only ever going to be externally powered from a genny there is no need for an IT or GI. 

If both the genny and inverter have a floating output then an RCD would achieve nothing, however if they can both be N-E linked then it would be a good idea to do so and add an RCD as an extra layer of protection. 

We are off grid so will be relying on generator power and the inverter when only lighting is required. I'll be fitting a single solar panel at some point.

on the subject of an RCD would it be wiser to fit a garage consumer unit with 2 MCB's and an RCD? I have a generator only lead with bonded N & E.

[Robbo]

23 minutes ago, Cloudinspector said:

We are off grid so will be relying on generator power and the inverter when only lighting is required. I'll be fitting a single solar panel at some point.

on the subject of an RCD would it be wiser to fit a garage consumer unit with 2 MCB's and an RCD? I have a generator only lead with bonded N & E.

A garage consumer unit is commonly used for this purpose, you may find it cheaper to buy the individual parts tho, especially if you want to use different rated MCB's.

Edited April 27, 2017 by Robbo

[WotEver]

40 minutes ago, Cloudinspector said:

on the subject of an RCD would it be wiser to fit a garage consumer unit with 2 MCB's and an RCD? I have a generator only lead with bonded N & E.

In addition to what Robbo observed above it would be worth investigating if the inverter can be N-E bonded as well. 

Edited April 27, 2017 by WotEver
Autocorrect decided that Robbo should be Robbie

[Cloudinspector]

Cheers folks. Priceless advice.

[Cloudinspector]

On 27/04/2017 at 07:02, WotEver said:

You don't show the charger. That should be fed from the shore power inlet before the change-over switch. 

Just a thought on this. Would wiring it in this way be a BSS fail as it's not going through the consumer unit?

[WotEver]

6 minutes ago, Cloudinspector said:

Just a thought on this. Would wiring it in this way be a BSS fail as it's not going through the consumer unit?

Yes

There would need to be at least an MCB or RCD between incoming and charger. 

See 3.9.2: https://www.boatsafetyscheme.org/media/268789/ecp-private-boats-ed3_rev2_apr2015_public_final.pdf

[Guest]

15 minutes ago, WotEver said:

Yes

There would need to be at least an MCB or RCD between incoming and charger. 

See 3.9.2: https://www.boatsafetyscheme.org/media/268789/ecp-private-boats-ed3_rev2_apr2015_public_final.pdf

I got around this  by fitting a socket with incorporated RCD, into which I plug the charger (I had same problem originally, where inverter could theoretically try and charge batteries.) Passed several BSC's now.

[WotEver]

46 minutes ago, catweasel said:

I got around this  by fitting a socket with incorporated RCD, into which I plug the charger (I had same problem originally, where inverter could theoretically try and charge batteries.) Passed several BSC's now.

Yup, that would be fine (as you already know of course)

[Mikexx]

On 27/04/2017 at 07:49, WotEver said:

If both the genny and inverter have a floating output then an RCD would achieve nothing, however if they can both be N-E linked then it would be a good idea to do so and add an RCD as an extra layer of protection. 

 

I believe it is practice to fit a NE link and to have an RCD. The links could be at the inverter so not to affect the generator wiring or if a shore line is ever used (with either a galvanic isolator or isolating transformer).

In the OP's case I would have thought a RCBO would be more simpler for a single circuit. YMMV.

[WotEver]

1 minute ago, Mikexx said:

I believe it is practice to fit a NE link and to have an RCD.

Only on those inverters which can be N-E linked. Centre-tapped ones for instance can't be. 

[Guest]

37 minutes ago, WotEver said:

Only on those inverters which can be N-E linked. Centre-tapped ones for instance can't be. 

Agreed. It can turn nasty!

[Cloudinspector]

I've found these at screwfix. If I've understood correctly they will do the job.

http://www.screwfix.com/p/british-general-13a-rcd-fused-spur-metal-clad/4323p

[WotEver]

Just now, Cloudinspector said:

I've found these at screwfix. If I've understood correctly they will do the job.

http://www.screwfix.com/p/british-general-13a-rcd-fused-spur-metal-clad/4323p

That would make for a neat and tidy job

Use in conjunction with one of these:

http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851

[Cloudinspector]

4 minutes ago, WotEver said:

That would make for a neat and tidy job

Use in conjunction with one of these:

http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851

For cable entry into the back box?

[WotEver]

Just now, Cloudinspector said:

For cable entry into the back box?

Well, I was assuming (always dangerous!) that the mains from the shore socket would enter from the rear with the hole protected by a grommet. But the cable out to the charger would use a gland like I linked - either from the side or bottom knockout, as applicable  

[Cloudinspector]

2 minutes ago, WotEver said:

Well, I was assuming (always dangerous!) that the mains from the shore socket would enter from the rear with the hole protected by a grommet. But the cable out to the charger would use a gland like I linked - either from the side or bottom knockout, as applicable  

Yep you assumed correctly