Consumer unit

[Nigel_Ward]

I think you need a metal box for the panel. This recommendation was brought in for fire protection.
Also you need a 2 pole RCD and 2 pole MCBs. This is what is shown in the 18th edition electrical regulations in the section on marinas and connections to boat installation.
Alastair Garrod (electrics afloat) also says you need 2 pole MCBs.
Another way for a very simple installation is to fit an RCBO (combined 2 pole RCD and 2 pole MCB.

 

[PaulRainbow]

I think you need a metal box for the panel. This recommendation was brought in for fire protection.

It was indeed brought in for fire protection, but you can still use plastic consumer units if they are housed in a metal cabinet. The regulation only applies to consumer units fitted within domestic buildings. Boats are not domestic buildings.

Also you need a 2 pole RCD and 2 pole MCBs. This is what is shown in the 18th edition electrical regulations in the section on marinas and connections to boat installation.

There is no requirement for double pole MCBs, as i have said many times in this thread. Boats are not marinas and are not subject to 18th edition domestic regulations. New build boats have to be built to standards set out in ISO13297 (2022), which does not make double pole MCBs madatory. Retrofit work on boats is not covered by any regulations.

Alastair Garrod (electrics afloat) also says you need 2 pole MCBs.
Another way for a very simple installation is to fit an RCBO (combined 2 pole RCD and 2 pole MCB.

Not read his book, but if he states that 2 pole MCBs are a requirement, he is incorrect.

 

[Boater Sam]

You need a double pole isolating switch and one 6A and one 16A double pole RCBO each of which use 2 ways in the box so you need a consumer unit with 6 ways in total.

 

[Rafal]

FuseBox RTAMB32 32A Double Pole B Curve 6kA 30mA Type A Mini RCBODefault Title One of many double pole RCBO using one way only.

 

[dankilb]

This is an interesting discussion - not least as I've not installed/assembled our new CU (for which I currently have 1P MCBs and 2P RCD - and require all 5 available ways for 3 circuits).

I had associated double pole RCBOs as bulkier (2 ways) and costlier. The above link suggests otherwise.

I'm not averse to switching out my 1P MCBs for 1P+N RCBOs. However, I'm still not clear what I gain by this? I don't care about the 18th edition or caravans or anything else. Our boat is setup not to draw reverse polarity power (we have two indicators and never plan to ignore them). I'd never work on anything AC without unplugging from shore power completely (so no risk of flipping an MCB and assuming L+N on that circuit are safe to touch).

What am I missing?!

 

[PaulRainbow]

You need a double pole isolating switch and one 6A and one 16A double pole RCBO each of which use 2 ways in the box so you need a consumer unit with 6 ways in total.

Could you explain why he needs these ?

 

[Rafal]

Spending more and more money? Mcb is £3, RCBO £30, now recommended AFDD £100

 

[PaulRainbow]

This is an interesting discussion - not least as I've not installed/assembled our new CU (for which I currently have 1P MCBs and 2P RCD - and require all 5 available ways for 3 circuits).

I had associated double pole RCBOs as bulkier (2 ways) and costlier. The above link suggests otherwise.

I'm not averse to switching out my 1P MCBs for 1P+N RCBOs. However, I'm still not clear what I gain by this? I don't care about the 18th edition or caravans or anything else. Our boat is setup not to draw reverse polarity power (we have two indicators and never plan to ignore them). I'd never work on anything AC without unplugging from shore power completely (so no risk of flipping an MCB and assuming L+N on that circuit are safe to touch).

What am I missing?!

The system you described will comply with current standards for a new build boat, it provides overload protection and protection from electric shock.

There is nothing to stop you fitting RCBOs for each circuit, if you choose to do so, doing so would mean that an Earth fault in one circuit only trips that circuit, not all three. Useful in your house, do you need it on the boat ?

 

[Boater Sam]

FuseBox RTAMB32 32A Double Pole B Curve 6kA 30mA Type A Mini RCBODefault Title One of many double pole RCBO using one way only.

Not seen this make before, smart. And not too expensive at less than £17 either, I am used to Schneider gear.

 

[Seastoke]

Whilst having a RCD on the boat is a must , you will find if you develop an earth fault that 99% will trip the RCD on the jetty , so fitting RCBO.s is a waste of money.

 

[Tranona]

FuseBox RTAMB32 32A Double Pole B Curve 6kA 30mA Type A Mini RCBODefault Title One of many double pole RCBO using one way only.

I looked at that type which is meant for caravans - in fact actually bought one before I realised that it is not suitable for a boat where you need at least 2 circuits - one for the ring main and the other for the battery charger plus possibly a third for the immersion heater in a calorifier.

Quickly came to the same conclusion as others that the simple CU sold for garage use is perfect for the job and effectively the same as the boxes fitted as OE in new boats minus the polarity indicator. If concerned about polarity a simple tester is all that is needed plus a conversion lead. Older caravans and camper vans that go to Europe are very familiar with this, but for the vast majority in the UK it is a red herring.

Not sure why some people in this thread and the other one on reverse polarity have to make it all so complicated when the supposed problems they talk about don't seem to be an issue in practice and the latest standards do not recognise them as issues. Furthermore new boat installations do not follow the the "solutions" they suggest, so unsurprisingly they never suggest the actual equipment that you can buy.

 

[PaulRainbow]

I looked at that type which is meant for caravans - in fact actually bought one before I realised that it is not suitable for a boat where you need at least 2 circuits - one for the ring main and the other for the battery charger plus possibly a third for the immersion heater in a calorifier.

You can fit multiple RCBOs, one for each circuit.

Quickly came to the same conclusion as others that the simple CU sold for garage use is perfect for the job and effectively the same as the boxes fitted as OE in new boats minus the polarity indicator. If concerned about polarity a simple tester is all that is needed plus a conversion lead. Older caravans and camper vans that go to Europe are very familiar with this, but for the vast majority in the UK it is a red herring.

Not sure why some people in this thread and the other one on reverse polarity have to make it all so complicated when the supposed problems they talk about don't seem to be an issue in practice and the latest standards do not recognise them as issues. Furthermore new boat installations do not follow the the "solutions" they suggest, so unsurprisingly they never suggest the actual equipment that you can buy.

Spot on