Any electricians here?

[jfgw]

It would be interesting to know what brands of MCB keep failing. It is possible Mike4 has to carry only a couple of different brands

I have known a Chint MCB supplying an immersion heater to fail. I have also known two ABB RCBOs supplying commercial lighting to fail.


Julian F. G. W.

[Mike4]

It would be interesting to know what brands of MCB keep failing. It is possible Mike4 has to carry only a couple of different brands

I have known a Chint MCB supplying an immersion heater to fail. I have also known two ABB RCBOs supplying commercial lighting to fail.


Julian F. G. W.

Curiously much of that type of work has dried up now that a big player has barged into my market with a much better website than mine and hoovered up all the work. Which is fine with me as I've grown weary of visiting town centre developments because parking gets ever more difficult and I need to work less (if at all).

But getting back on topic, on refection the first time I encountered a RCBO was when one had failed in a consumer unit in a posh city centre new development feeding a thermal store and some googling was needed to work out why it had the extra wire. I'm pretty sure it was some odd Chinese brand - not a mainstream brand I'd heard of. One of the rare occasions I had to make a return trip to fix a boiler! But I let myself off that as it wasn't actually a fault with the boiler I'd been called out to fix...

[Spot5]

The breaker you linked to is 32A. That is fine for up to 7.5 kw,
but for 8kw 40A is needed.

https://www.tradesparky.com/circuit-pro ... a-30ma-6ka

Alternatively, can you adjust the chargiing current from the car to be 30A or less?



Cheers,
S

[Mike4]

The breaker you linked to is 32A. That is fine for up to 7.5 kw,
but for 8kw 40A is needed.

https://www.tradesparky.com/circuit-pro ... a-30ma-6ka

Alternatively, can you adjust the chargiing current from the car to be 30A or less?



Cheers,
S

Interesting point which also assumes mains voltage is 240, when the spec nowadays iirc is for 230Vac.

Also relies on the efficiency of the charger being 100% which seems unlikely, and the power factor being 1. Not something that can be relied upon I'd have thought.

Net conclusion is the RCBO is badly undersized!

[9873210]

The breaker you linked to is 32A. That is fine for up to 7.5 kw,
but for 8kw 40A is needed.

https://www.tradesparky.com/circuit-pro ... a-30ma-6ka

Alternatively, can you adjust the chargiing current from the car to be 30A or less?



Cheers,
S

Interesting point which also assumes mains voltage is 240, when the spec nowadays iirc is for 230Vac.

Also relies on the efficiency of the charger being 100% which seems unlikely, and the power factor being 1. Not something that can be relied upon I'd have thought.

Chargers are not passive devices like resistors. Limits and power factor depend on the logic in the charger (almost always software) not directly on Ohm's law. They are required, by law, to have a power factor quite close to 1. They can also limit the current directly, thus charging at higher or lower power depending on the supply voltage; this is certainly required by good engineering practice if not by law. If the efficiency is less than 100% the battery charges slower, the power supply does not draw more current to compensate.

Unlike a lot of other things the current limits should do what it says.

[Urbandreamer]

Back to the original weather tripping.

Amazon provided a link to a "glove" that protects the plug at the car end from the weather. Unfortunately it attaches to the car magnetically, which won't work on an I3 unless you remove the plastic wing and fit something magnetic behind it. It's intended for EV's made of iron.

However searching for other I3 related stuff, I found someone using a garden tap cover to protect the plug from the weather.
https://www.youtube.com/watch?v=NR5zdf56pm8

Why am I searching? Well months ago I was impressed by the OP's review of their I3 and decided to research it. After my touring holiday in summer I intend to buy one. No car would be ideal for me and the I3 has a couple of issues that I'm sure will irritate, but on the whole it's what I want.

[forgotusername]

Wow, so many replies and ideas for which I am grateful. The novelty modified water tap protector certainly looks like it would keep out the rain.

I checked with the suppliers of my existing RCBO, taking on board the requirement that any replacement should be from the same manufacturer and they confirmed that they cannot do a like for like replacement. My charger is rated at 7.2kw but reading Mike4's comment about a 40 amp one, I found it is in stock and am minded to get one. Apart from needing to find an electrician to fit it, is there any downside in overspeccing the protection?
https://www.tradesparky.com/circuit-pro ... a-30ma-6ka

Urbandreamer, I'm glad you found my review of the i3 useful. Having had the car for a few years now, I can honestly say it is a delight to use. My wife, originally sceptical, loves it. The steering is light, the turning circle is comparable to a London taxi. It's quiet and very rapid off the mark making overtaking when room is tight, a breeze as the power is instantaneous. You can get past a slower vehicle before you know it. Handling is sharp and accurate with rear wheel drive and only very occasional wheel spin if you "boot it".

Reliability has been good with just two repairs needed, top rubber mounts on the front springs were worn and got replaced. The UJ on the steering column is worn so booked in for replacement on Monday. Annual mileage is about 6000 and the car has covered about 28k miles.

Downsides are few, the ride is firm but acceptable to me. Those used to softly sprung cars might find it takes time to get used to. Range is another one. I have the Rex model which uses a small BMW motor bike engine running on Petrol to charge the battery if it runs out of electrical power. Combined range is about 180 miles before you need to add more petrol or visit a charging station. Newer models are all electric but with a bigger battery pack so, I think the range is similar but no back up as with the Rex version. Last summer we travelled to a holiday cottage at the limit of the range. The petrol motor fired up when we ran low on charge and we arrived at our destination where there was a charger available. I took the precaution of stowing a couple of extra petrol cans just in case. I wouldn't want to push far beyond the 180 miles limit though unless charging stations could reliably be found.

The car is great around town and has become our "shopping trolley". My new Octopus tariff allows me to charge overnight at just 9p per kWh so a typical charge would result in the equivalent of 3p per mile. For my sins, I have owned a beautiful E93 BMW M3 convertible since 2010 which has a V8 engine costing approx 30p per mile. It's exhilarating to drive if you can find a road without pesky speed cameras but I think I'm getting too long in the tooth for it so plan to sell it and buy another EV with a far bigger range.

Good luck in finding an i3 "goodun"

[Urbandreamer]

I took the precaution of stowing a couple of extra petrol cans just in case. I wouldn't want to push far beyond the 180 miles limit though unless charging stations could reliably be found.

On that subject, it is something that I have been researching. Charging points are far more common than many realize.
You can check for free, charging stations in a given area using:
https://www.zap-map.com/live/
They do an app with route planner, for a price.
However research shows that while it is good, the money is better spent on ABRP.

[9873210]

Apart from needing to find an electrician to fit it, is there any downside in overspeccing the protection?

Yes. The overcurrent protection primary purpose is to prevent the wires and other parts of the circuit from overheating and potentially causing a fire. If you overspec it, you lose that protection.

If you consult an electrician he might inspect the entire circuit and uprate the breaker if everything was oversized for the existing breaker, but an incredulous stare, followed by a good talking to is more likely.

[Urbandreamer]

Apart from needing to find an electrician to fit it, is there any downside in overspeccing the protection?

Yes. The overcurrent protection primary purpose is to prevent the wires and other parts of the circuit from overheating and potentially causing a fire. If you overspec it, you lose that protection.

If you consult an electrician he might inspect the entire circuit and uprate the breaker if everything was oversized for the existing breaker, but an incredulous stare, followed by a good talking to is more likely.

I'm sure that any electrician would point out that there is a very significant difference between a RCBO and a MCB (replacement for fuses).
The RCBO has nothing to do with over current and it's spec, in terms of Amps, is how much it can safely pass and switch.

It's job is NOT to protect the wires. It has a far more important job. (look it up)

BTW, do you know how the wires are run? It does make a VERY significant difference. You need bigger wires if you embed them in plaster, than if you tack them to the walls of a garage. That WILL effect MCB's. If in plaster the cables will be 10mm. If not, then 4 or 6 mm.

FWIW, while not a qualified electrician, I am/was an electrical engineer, amongst other things.

Ps, I note that forgotusername asked about RCBO's, not as you assume MCB's.

[csearle]

I'm sure that any electrician would point out that there is a very significant difference between a RCBO and a MCB (replacement for fuses).
The RCBO has nothing to do with over current and it's spec, in terms of Amps, is how much it can safely pass and switch.

It's job is NOT to protect the wires. It has a far more important job. (look it up)

That is simply not the case. RCBO stands for Residual current Circuit Breaker with Overcurrent protection. As well as the residual current protection it does exactly the same job as an MCB (or a fuse) in protecting the cable from overcurrent and therefore from overheating.

Chris

[Urbandreamer]

I'm sure that any electrician would point out that there is a very significant difference between a RCBO and a MCB (replacement for fuses).
The RCBO has nothing to do with over current and it's spec, in terms of Amps, is how much it can safely pass and switch.

It's job is NOT to protect the wires. It has a far more important job. (look it up)

That is simply not the case. RCBO stands for Residual current Circuit Breaker with Overcurrent protection. As well as the residual current protection it does exactly the same job as an MCB (or a fuse) in protecting the cable from overcurrent and therefore from overheating.

Chris

Thanks for the correction. I confess that I'm more familiar with RCBO's covering multiple circuits, each with a MCB in the domestic situation.
They are not widely used in the industrial installations that I'm more use to.

[jfgw]

Thanks for the correction. I confess that I'm more familiar with RCBO's covering multiple circuits, each with a MCB in the domestic situation.
They are not widely used in the industrial installations that I'm more use to.

I think you are confusing RCBOs with RCDs still.

Just to clarify,

An MCB (miniature circuit breaker) does the job of a fuse;
An RCD (residual current device) is designed to trip if there is an earth fault. It may be marked "RCCB" (residual current circuit breaker), which could be the confusing bit;
An RCBO combines the two. It is not normally used to provide RCD protection to more than one circuit.

HTH.


Julian F. G. W.