Structural Steel

uksparks · Jan 15, 2015

Hi,

Following my threads about using structural steel for the earth...

Well, today was in the area and stopped by the office where the EV charger is going and they are building this building right next door to it, its exactly the same, I stopped and as it happens I managed to speak with the bloke who actually with his very own hands built the office the unit I will be working on.

Anyway, I thought you would like to see some photos of the construction of it so you can see how well its fixed to the ground.

He said there are well over 100 Bolts which are are massive bolts, not little things, they are connected to the ground with 400mm bolts into the concrete which each concrete chunk is 1000mm into the ground.

The Ra should be very good I would imagine. Ill be able to tell you on Saturday when I do the job.

[ElectriciansForums.net] Structural Steel

uksparks · Jan 16, 2015

I am sure it will be full of it so we shall see, hopefully it will not come to it and the building steel will be adequate.

I am armed with all the figures I need to achieve so should be ok, like I say, if it means I have to go back to put rods in, then so be it.

SPARTYKUS · Jan 16, 2015

Engineer54 said:
So long as you're not thinking about using those 3/8'' short thin twigs as earth electrodes!! You'll need at least two 5/8'' extendable rods coupled together at each rod location if you want to stand any chance of attaining a decent Ra value....

Going by the state of those photo's you posted of the other building under construction, you may well find that the ground around the building you're working on is full of rubble and building debris!! So be warned!!

in my best South West accent, "brashy"

uksparks · Jan 17, 2015

As promised, I installed the car charger today, looks sodding good, I'm so pleased with it.

I disconnect the water bond at the water, I even disconnected the main earthing conductor at the cutout, and then just did a Ze to the Steel bond and got a result of 0.16 Ohms. Which is totally compliant in my book, I cannot see where else that figure was coming from other than the steel, I can only assume it was the steel structure.

I did however as I said I was going to, run a 25mm earth from the car charger back to the steel of the building too for good measure, 25mm only because I was given it and had it spare laying around.

Im happy, the customers happy, everyone's happy. A long day, but a job well done!

I had to dig a trench too, did it only 500mm deep, used a bit of 50mm suction hose for ducting. I have also left some 25mm coiled up under the ground just outside the charger in case it needed hooking up to a rod or two.

bossian · Jan 17, 2015

Neat, tidy and compliant....well done

sammyshooter · Jan 17, 2015

@uksparks, lovely job, great mentality, and a big thank you for sharing.

uksparks · Jan 17, 2015

It was a long old day, started at 9.30, finished at 7:30, I didn't stop, it just took ages as I did a good job and had to do all the ground work too and lay slabs and concrete etc and feed the cable across ceiling and fit electric meters too.

sammyshooter · Jan 17, 2015

Did the weather hold out for you?

uksparks · Jan 17, 2015

Yes it was nice actually.

Knobhead · Jan 18, 2015

The reason I pointed out the possibility of isolated plinths, I fell foul of a steel chimney that was fixed using rock anchors. The anchors were embedded in epoxy grout. I had to run 2x75mm[SUP]2[/SUP] tapes to the plant main steel work.

Sometimes the concrete plinth is “tanked” with bitumen before the infill goes in, again pretty well isolated.

ImpededLoop · Jan 18, 2015

Good result, well done.

How did you get the cables through the cladding in the end?

uksparks · Jan 18, 2015

I cut a hole in the cladding with a cone drill, and went all the way through, about 3", then carefully fed it through, it went through fine in the end, I had to elongate the hole, then filled it all in nicely with some black roofing mastik stuff.