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Ladies and Gents,

I'm trying to get my head around the wiring, up to the distribution board, so I've made a little diagram to see, in simple terms, how things are wired, what I need to buy and what I might be missing. I'm looking for criticism on my layout and advice on where RCD's are required, as Im a bit confused about their siting.

I know there's some electrical gurus on here. Thanks in advance

Untitled Diagram.jpg

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It's imperative you have an RCD after the inverter part of your Victron together with earth/inverter neutral strap to provide clear conditions for safety trip when AC is being provided by battery power. The latter should be provided by the Victron with automatic disconnention of this strap when shore power is passed through the Victron to your AC distribution sockets. 

An RCD on the shoreline feed to Victron would be optional since there would (should) be one on the shore power pedestal protecting downstream.

ETA:  the galvanic isolator should be fitted immediately after shore power inlet.

Edited by by'eck
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56 minutes ago, Catnip King said:

Shoreline should plug into RCD then go to Inverter. 

No. Well you could put one there if you really wanted to or if it was a long way from the inlet to the Combi. But the main need for an RCD and MCB (or RCBO) is after the Combi.

Regarding the diagram, I'm wondering why you show a primary and secondary 230VAC feed? Normally one is enough! That said, some folk like a feed from the shore side of the inverter to an immersion heater so it can't be powered from the inverter, but others like me like to be able to decide if they want to run the immersion from the batteries (augmented by the engine alternator, hopefully). I also suggest that the big block you show as AC/DC distribution is best considered to be two seperate things. Don't mix 12v with 230v or it will all end in tears!

Edited by nicknorman
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5 minutes ago, Mohsen said:

Would you put it before or after the galvanic isolator ?

As explained above, it should go after the Multiplus, not before it,  but even if it was wired before it, a GI has no bearing on the wiring because an RCD only has Live & Neutral connected to it. 

1 hour ago, Mohsen said:

Untitled Diagram.jpg

It's only a minor thing but I presume that "DC Link Box" means Pos & Neg busbars? If so then that's where the DC feed for the distribution panel comes from too. 

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1 minute ago, WotEver said:

As explained above, it should go after the Multiplus, not before it,  but even if it was wired before it, a GI has no bearing on the wiring because an RCD only has Live & Neutral connected to it. 

Ahh, good info. Thanks. Does any of the DC need an RCD ? What about an RCD before the distribution board (Im intending to use a simple panel with fused switches and no RCD).
 

11 minutes ago, by'eck said:

It's imperative you have an RCD after the inverter part of your Victron together with earth/inverter neutral strap to provide clear conditions for safety trip when AC is being provided by battery power. The latter should be provided by the Victron with automatic disconnention of this strap when shore power is passed through the Victron to your AC distribution sockets.

Thanks... Im having to read around this statement to understand what you mean, but it seems to be useful info :D

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I didn't say put before inverter I mean an extra one before inverter. I have 2 on my boat one before and one after. I got shore supply only stuff connected to one before and then when I cruise I rely on the other one.  Hope that makes sense.

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2 minutes ago, WotEver said:

Also... "AC Distribution" means "Consumer Unit" and this will contain the RCD. 

Show DC and AC as two separate boxes - because they are :)

BlueSea do panels that contain 12vdc and 230vac fused switches. I figured since I wont have much 230vac (kitchen ring & rest of the boat ring) a panel that includes 4 fused switches for 230vac would provide me with all I need and be a neater solution than having 2 consumer units.

https://www.bluesea.com/products/8084/AC_Main_%2B_6_Positions_DC_Main_%2B_15_Positions

Like this one but not this particular one.

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Just now, Mohsen said:

Thanks... Im having to read around this statement to understand what you mean, but it seems to be useful info :D

Lemme explain.  

When shore power is connected this passes through the Multiplus and thence to the RCD within the Consumer Unit. Shore power (in simple terms) has a connection between Neutral & Earth which is made (usually) at the substation. This connection between N & E is fundamental to why an RCD protects you. Even if the Multiplus is 'assisting' the shore power that N-E link is still there, provided by the shore power.

When you have no shore power all of the mains AC is generated by the Multiplus. In this mode the Multiplus itself must provide the link between N & E. It does this automatically. 

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13 minutes ago, Catnip King said:

I didn't say put before inverter I mean an extra one before inverter. I have 2 on my boat one before and one after. I got shore supply only stuff connected to one before and then when I cruise I rely on the other one.  Hope that makes sense.

My view is that it's superfluous since the shore bollard has one. Thus you are protected by it and don't really need another RCD at all when on shore power. You only need a boat-side RCD when on inverter power. However the regulations relating to Recreational Craft Directive tend to agree with you. Of course the BSS doesn't require an RCD, just recommends it.

 

edited to say "Oops, no the Rec Craft Dir doesn't agree with you at all, I was thinking of circuit breakers not RCDs. So the position is that I, the European Technocrats, and the BSS, all think your extra RCD is pointless."

Edited by nicknorman
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3 minutes ago, Mohsen said:

BlueSea do panels that contain 12vdc and 230vac fused switches. I figured since I wont have much 230vac (kitchen ring & rest of the boat ring) a panel that includes 4 fused switches for 230vac would provide me with all I need and be a neater solution than having 2 consumer units.

https://www.bluesea.com/products/8084/AC_Main_%2B_6_Positions_DC_Main_%2B_15_Positions

Like this one but not this particular one.

No, you MUST have a Consumer Unit to comply with the BSS

7 minutes ago, Catnip King said:

I didn't say put before inverter I mean an extra one before inverter. I have 2 on my boat one before and one after. I got shore supply only stuff connected to one before and then when I cruise I rely on the other one.  Hope that makes sense.

I'm guessing you don't have a Multiplus. OP does. 

10 minutes ago, Mohsen said:

Does any of the DC need an RCD ?

No. 

3 minutes ago, WotEver said:

No, you MUST have a Consumer Unit to comply with the BSS

Of course, if you wish to then feed from the consumer unit to the pretty BlueSea panel then you can do. 

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24 minutes ago, nicknorman said:

I'm wondering why you show a primary and secondary 230VAC feed? Normally one is enough!

Oh, Nick's added to his post...

Note that if you have two AC feeds as you show, you will require two RCDs. 

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12 minutes ago, nicknorman said:

edited to say "Oops, no the Rec Craft Dir doesn't agree with you at all, I was thinking of circuit breakers not RCDs. So the position is that I, the European Technocrats, and the BSS, all think your extra RCD is pointless."

So do I unless he has two separate AC circuits - one from shore power and one from inverter. 

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23 minutes ago, Mohsen said:

BlueSea do panels that contain 12vdc and 230vac fused switches. I figured since I wont have much 230vac (kitchen ring & rest of the boat ring) a panel that includes 4 fused switches for 230vac would provide me with all I need and be a neater solution than having 2 consumer units.

https://www.bluesea.com/products/8084/AC_Main_%2B_6_Positions_DC_Main_%2B_15_Positions

Like this one but not this particular one.

On the AC side and bearing in mind the max current limit of boat systems, there is no point in having 2 ac "rings" and in fact no point in having an ac ring at all, just use 2.5mm^2 cable in either a star or daisy chain to the sockets and other ac services. You just need one consumer unit with one breaker, which could be an RCBO. Or one MCB and one RCD.

If you want to comply with the Rec Craft Directive just bear in mind that if the distance from the shore inlet to the consumer unit exceeds 3m (cable trunked/in conduit) or 0.5m (unprotected cable) you should have another breaker within those distances. But this is not normally an issue on a narrowboat if you trunk the cable, unless you want to have a shore inlet at the front as well as one at the back.

Edited by nicknorman
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19 minutes ago, WotEver said:

So do I unless he has two separate AC circuits - one from shore power and one from inverter. 

But even then, only if you plug the boat into some gash socket dangling out of someone's house window (house with old wiring not having an RCD). If you only plug into a proper bollard, there is already an RCD in circuit. No point in having two in series.

Edited by nicknorman
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7 hours ago, nicknorman said:

But even then, only if you plug the boat into some gash socket dangling out of someone's house window (house with old wiring not having an RCD). If you only plug into a proper bollard, there is already an RCD in circuit. No point in having two in series.

Very true. 

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On 02/06/2017 at 00:06, WotEver said:

No, you MUST have a Consumer Unit to comply with the BSS

Of course, if you wish to then feed from the consumer unit to the pretty BlueSea panel then you can do. 

Am I right in thinking I could use an MCB like the link posted below, before the pretty BlueSea panel?
(Assuming the fuse was rated correctly)

https://www.alertelectrical.com/cudis-cpn-3-way-shower-consumer-unit-with-40a-mcb-cu03-1.html?gclid=CNiPr9HqqdQCFSex7Qodr74Bdw

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13 minutes ago, WotEver said:

Yes, much more elegant - I changed the MCBs to 16 amps for the sockets, 3 amps for isolated shaver sockets in the bathroom and loo, and 6 amp for the immersion heater. I keep 240v A/C  well away from any low voltage DC (mainly to avoid and 'belt' from inadvertedly   touching the mains while fiddling around with 12/24v kit....

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