Speak EV - Electric Car Forums banner

Looped 60A

4K views 20 replies 12 participants last post by  Drewby80 
#1 ·
147508

I don't think its right.
If I would put oven on or heating(underfloor heating) or neighbour will turn on electric shower it will be blowing fuses.
Any idea what can I do about it?
 
See less See more
1
#2 ·
If you are concerned might be worth calling Ryan (number on the top right of the letter) and having a quick chat about your setup. Explain that you understand what he’s saying about don’t exceed it, but there will be times it’s unavoidable and ask what options there are. Worst case he reassures you everything is fine and correct, there’s nothing to loose from asking the question? (Unless he says “oh, you’ll need unlooping at your own cost… 😬)
 
#4 ·
Worth remembering that a 60 A main fuse won't blow at 60 A. In fact even at 80 A it would need that current to flow for around 3 hours to blow. In reality, diversity means that most high loads, like a cooker, shower etc will only be running at full power for a short time, and not long enough to blow the main fuse.
 
#7 ·
I believe those rules are already in place.

I suspect Northern Power grid are hoping the OP will not be aware of this rule.

That said unlooping may cause some disruption (ie digging up the drive / garden) and may be a challenge if the unlooping requires work on the neighbour's property which the neighbour refuses.

Unlooping and DNO fuse upgrade will give the best future proofed solution - a load sensing charger may be the solution with least effort / disruption.
 
#8 ·
Whilst @Jeremy Harris is correct about the fuse only blowing well above the rated value, diversity etc. it's a good idea to take advantage of the current rules requiring the DNO to do the unlooping for free. Power usage is only likely to increase in the future with the switch to heat pumps and the low cost overnight tariffs or the time of your usage may change meaning that you want to charge at a time when you have other significant loads. Kicking the can down the road is for politicians and others who move on before the problems come home to roost, so unless you plan to move soon get it done.
 
#9 ·
I agree, push the DNO to unloop, but they can decide to dig their heels in and refuse, if the existing supply is deemed adequate. The current rule doesn't mandate that a DNO has to unloop a supply, all it mandates is that they must ensure a supply of sufficient capacity to allow car charging, in addition to the house normal load, is available

Some DNOs will just unloop supplies without hassle, some need persuading, and some may just say there is no need to do it, and if they can show that the supply is adequate to deliver the existing house load plus a 32 A charge point then they cannot be forced to increase it further.

At the moment, they are stating that the supply is adequate, as long as the house load doesn't exceed 45 A (with a diversity allowance). They could prove this easily by fitting a load monitor on the supply for a week to see what the actual house demand is. If they find it's less than the 45 A they've allowed, then they can just do as they have said, and leave it at 60 A.
 
#10 ·
At the moment, they are stating that the supply is adequate, as long as the house load doesn't exceed 45 A (with a diversity allowance). They could prove this easily by fitting a load monitor on the supply for a week to see what the actual house demand is. If they find it's less than the 45 A they've allowed, then they can just do as they have said, and leave it at 60 A.
I believe the "in practice" is irrelevant, it is the theorectical which counts. Might sell the house next week and the new occupant will behave differently. If the DNO plays up threaten to and then do complain to Ofgem, they dont like that as there is a cost to them and blotting the copy book.

An electric shower 45A (no diversity), a car charger 32A and the rest is way over 60A . 60A is useless in this day never mind about tomorrow.
 
#12 ·
The requirement isn't just to support EV charging but also A/GSHP. There's also no requirement to complete the work, so you could be disingenuous and say that you plan to fit 2 x charge points and a 7kW heat pump meaning that you'd be pushing 100A on those alone. Just beware that they might insist that you install 3 phase which they can charge you an arm and a leg for.
 
#13 ·
Our heat pump is 7 kW. Uses less power than a kettle to run. You'd need a really big heat pump to require any supply upgrading, now that pretty much all of them are inverter controlled. The reality is that our 7 kW heat pump tops out at a bit under 2 kW input for the first minute or so after firing up, then settles down to run at about 800 W input. Something like a 25 kW heat pump would draw about the same as a charge point, and very few homes are ever going to need anything like that much heating.

As far as free supply upgrading is concerned, the DNO aren't under any obligation to do this for two charge point installations, only the first one. They don't like doing this if the local LV distribution network is already running at capacity, either, as if they need to do a PMT change, for example, the cost to them will be around £12k to £15k or so. They will try hard to find a way to wriggle out of doing anything for free that involves them in doing this sort of work, and I've heard a few horror stories of the prices they've tried to squeeze out of customers for just a modest upgrade. It's not unusual for this to be a sore point with self-builders, as often the DNOs (and the utility companies) view self-builders as way to get upgrades done to their local network on the cheap (Wessex Water tried exactly this trick with me).
 
#16 ·
Depends. Should be the installer, but there have been cases reported here of installation companies getting customers to do it, probably just them cutting corners, as the bottom line is that the installer is the one putting his/her signature on the chit to say a total load assessment has been undertaken and that the load will not exceed the supply capacity.


Can the DNO grant permission on the condition that the charge point has total-house load limiting ?
Generally the DNO don't grant permission. The process is that they need to be informed after the installation is completed, if it's just for a single charge point of up to 32 A. The onus is on the installer (i.e. the person physically carrying out the work) to do the total load assessment, and the installer can take the load limiting capability of a charge point that has it into account, in much the same way as they will take diversity into account for some other loads within the installation.
 
#19 ·
Generally the DNO don't grant permission. The process is that they need to be informed after the installation is completed, if it's just for a single charge point of up to 32 A. The onus is on the installer (i.e. the person physically carrying out the work) to do the total load assessment, and the installer can take the load limiting capability of a charge point that has it into account, in much the same way as they will take diversity into account for some other loads within the installation.
According to this flowchart, there are some circumstances where you need to apply to connect - I was wondering if they have the option to stipulate that load-limiting is implemented in cases where they might otherwise refuse.
 
#17 ·
I have a 60A main fuse on a looped supply (well it looks looped - two wires going into the cutout)
Installer was more than happy to install a Zappi with load balancing.
We don’t have electric heating or shower - only large load appliances are Oven, Dishwasher and Washer/Dryer.
I’ve not heard anything from DNO since the installer did all the paperwork for the grant etc. This was back in November 2020.
 
#21 ·
View attachment 147508
I don't think its right.
If I would put oven on or heating(underfloor heating) or neighbour will turn on electric shower it will be blowing fuses.
Any idea what can I do about it?
A looped supply cable can deliver at least 120A between both the properties.

You should be able to draw 60A each continuously all day long with no issues at all.

Depending on what else you use in the house they are correct that under the right circumstances that you can fit a 32A charge point on a looped supply.

You can get charge points that monitor the load on the mains incomer and reduce their current accordingly.

When western power distribution changed my incomer the fitted a 100A fuse to my looped supply and didn’t even flinch.

It depends on how big your cables are.

If you plan to charge on cheap rate electric overnight when everyone is asleep you should be able to 32A charge no problem.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top