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Entirely predictable ground loop

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Entirely predictable ground loop

Postby Andy__D » Tue Dec 29, 2020 2:05 am

My house was built in the 1950s, and was wired throughout with 2 core cable, no earth / ground. Whilst a house with 2 core cable should have only 2 pin plug sockets throughout, we have 3 pin sockets. When the survey was done, no issue was found. When I first went to rewire a plug socket (after it blew out in a lightning storm and took the TV and Mac mini with it...) I found out why - all the earth pins in our sockets are wired (with an extra 'jump' wire) to neutral - which makes a plug-in socket tester show green, even though it really isn't safe.

As you would expect, I'm getting ground loop hum on any music equipment I plug in throughout the house.

I know what I need to do is call in an electrician and get the house re-wired, and, when I have the money to be able to afford to re-wire and re-decorate the house (as they'll need to cut a hole in the drywall to replace the cables at the very least, which will mean re-finishing and re-paining the walls - which will get particularly expensive behind the bathroom tiles and kitchen cabinets), that's exactly what I'll do.

In the short term, whilst I'm saving up, I was wondering if I could reasonably do the following:

1. Drill a small hole through the back of the socket in the main room where my music computer is through to the outside wall
2. install a new ground rod in the earth (I'm thinking new would be better than hooking up to the existing ground rod which is about 2 yards away, and is connected to the main board, but the only circuit that's wired with 3 wire connector is the 240v socket to the dryer, not sure if hooking up to that might cause interference?)
3. Run a new earth wire from the ground rod, through this hole into the socket, hook up to the earth / ground pin of the socket, and remove the join between the earth and neutral wires. (And then fill the hole with waterproof caulk).

Would it be reasonable to assume that this might help remove my ground loop hum (on just this one socket), and maybe even make it slightly less potentially lethal to plug a guitar amp in (which I currently don't dare do)?

I should note, as the circuit that this is on is also the bathroom circuit, we do have a GFCI (ground fault circuit interruptor) on the live and neutral wires, so surges should be picked up and the power cut, I wasn't really sure, as the earth would be entirely independent, if we might run into additional issues with having a GFCI on this circuit ( which we have to have, as the circuit goes to the bathroom)? I'm also not entirely sure, as the earth isn't connected, if it would do anything at all in a surge situation? In the bathroom, the socket that has the GFCI on it has its earth connected to the water pipe, as does our guest bathroom, but the other two sockets on that circuit have the earth pin bridged to the neutral connector.

I know the advice is likely to be "don't delay, get a sparkie in today" - but, the job will likely be not insignificant - I haven't told you the half of the horrors yet - like the dishwasher, fridge, washing machine and microwave all being wired into the outside shed lighting circuit, so you can only have two of them on at any one time - so if you can't run the dishwasher or use the microwave at night without turning out the lights, else it'll trip (and I don't like going to the power board to flip the jumpers late at night because we get a lot of snakes at night in our yard - mostly harmless, but they freak me out - as well as there being a very angry possum living in our side alley)...

Any advice gratefully received!
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Re: Entirely predictable ground loop

Postby Watchmaker » Tue Dec 29, 2020 5:24 am

Please do not attempt to do this yourself. I used to run a construction company and have many things to say, starting with the insignificant stuff - you will run afoul of the planning and code enforcement people, thus ruining future important relationships, you will expose yourself to fines and other unpleasantness such as losing the ability to get home insurance...not to mention the significant extra costs for someone to fix it properly.

Borrow if you have to, anything but DIY here. If you feel ripped off on the purchase look into misrepresentation on the buyers behalf if they warranted the electric was up to code. As a fellow American, let me assure you, you can get royally screwed doing this yourself - and rightly so, people can die.

Remember that - if you screw it up, someone you love could die.
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Re: Entirely predictable ground loop

Postby wireman » Tue Dec 29, 2020 11:21 am

Just to be clear, what country is this house in?
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Re: Entirely predictable ground loop

Postby blinddrew » Tue Dec 29, 2020 11:31 am

I'd guess Florida, USA.
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Re: Entirely predictable ground loop

Postby Murray B » Tue Dec 29, 2020 11:59 am

Some questions and suggestions for a hopefully non contentious solution...

How far is the earthed socket (the one with the dryer connected) from where you want the studio set up?

How often is the dryer on and could you schedule it's use to avoid studio time and vice versa?

How much power do you need to run your set up?

Could you run an extension lead from the earthed socket to your studio space until you can get an electrician in and work when the dryer isn't running (do the drying overnight perhaps?) You'l need quite a heavy cable if it's a long way away and at the limit of power you can run from a single socket - take advice on this if you do it.

Alternatively could you employ an electrician to extend the earthed circuit to your studio space as an interim measure - this would be cheaper than a complete rewire.

I can't imagine that DIY alteration of your electrical circuit is going to be recommended by anyone on the forum.
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Re: Entirely predictable ground loop

Postby Andy__D » Tue Dec 29, 2020 12:16 pm

Watchmaker wrote:Please do not attempt to do this yourself. I used to run a construction company and have many things to say, starting with the insignificant stuff - you will run afoul of the planning and code enforcement people, thus ruining future important relationships, you will expose yourself to fines and other unpleasantness such as losing the ability to get home insurance...not to mention the significant extra costs for someone to fix it properly.

Borrow if you have to, anything but DIY here. If you feel ripped off on the purchase look into misrepresentation on the buyers behalf if they warranted the electric was up to code. As a fellow American, let me assure you, you can get royally screwed doing this yourself - and rightly so, people can die.

Remember that - if you screw it up, someone you love could die.

Thanks Watchmaker, that’s really good advice, I’d not thought of the code enforcement / insurance aspect to this - which would likely make an already expensive piece of work a lot more expensive. I do feel ripped off by the seller, I’ve already tried going down the path of getting reparations when I discovered that the laundry room drain wasn’t a drain at all, it was just a piece of pipe going in to the ground (not a French drain, just a stub of pipe) - so we have already had to repair flooding damage - the insurance company tried going after the seller, but no joy.

I’ll get an electrician and a general contractor in. As a former construction company owner, would you recommend places like Angie’s list for finding people to do this sort of work? Or is there a better way to find the good guys?

Thanks Murray B for your questions about the dryer, unfortunately, that’s a 240v circuit,in the shed on the other side of the house, and all my music gear is all 110v- so, whilst I see where you’re going with your question, I don’t think that’d be a practical solution, thanks! I will ask the electricians if they could do just one circuit, that’s a good idea, but I suspect they may not like the idea of leaving something unsafe on a job they’ve done.
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Re: Entirely predictable ground loop

Postby CS70 » Tue Dec 29, 2020 12:32 pm

Just one note, I second that for an electrical job of this magnitude an electrician is necessary, but when it comes to repairing holes in drywalls, muddying them and repainting, it is really something you can do yourself and save the cost of labour. It’s really easy to do a good job if you learn a little, and count the first wall as practice (I.e. you may end up doing four layers instead of three). You just need patience, and the money for materials (but, unlike contractors, you can target sales periods and special offers and save big also on materials).

I did three rooms on my own before running out of patience and calling someone to do the job for the others...but since it’s a time consuming task the difference in cost was huge.
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Re: Entirely predictable ground loop

Postby Sam Spoons » Tue Dec 29, 2020 12:37 pm

If no joy from the buyer have you considered going after the surveyor and/or the agent? The surveyor should have PLI to cover him for a negligence claim due to him not reporting the unsatisfactory wiring?
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Re: Entirely predictable ground loop

Postby Murray B » Tue Dec 29, 2020 1:42 pm

Just another thought as a solution - although it's not cheap it may be cheaper than an electrician...

How about a portable power bank that could produce about 500w at 110v ? They are sold for camping etc and would give you a totally isolated supply - you may need to add an additional ground for it but you aren't messing with the domestic electrics?

Edit - just looked at the price for a 1500Wh one - it's hideously expensive, maybe not a good plan after all sorry :-(
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Re: Entirely predictable ground loop

Postby ManFromGlass » Tue Dec 29, 2020 2:46 pm

+1 for hiring a pro electrician.
We had one come into our house and look at our fuse box. He said he was familiar with this 40 year old model and has replaced a lot of them lately as they have a tendency to burst into flames. We replaced it right away.
Aside from safety concerns having a pro do the work also means you can relocate receptacles and lights to suit your needs better. Don’t go too crazy as here they charge for extras like that.

To find a reputable electrician word of mouth is best. If you see any new builds you could also stop and ask the contractor for suggestions. Contractors are a good source for finding trades.

Lastly - if you end up doing drywall there are some horrible YouTube’s and some really good YouTube’s for instruction. I’ve been watching anything by Vancouver Carpenter for drywall tips. I am following his suggestions and it’s turning out much better than I hoped.
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Re: Entirely predictable ground loop

Postby gullfo » Tue Dec 29, 2020 6:35 pm

++1 on the properly licensed electrical contractor - permits, code compliance, proper grounding (esp FL with lots of electrical storms (i'm in PCB)).
even with an isolation UPS, the wiring is not safe as there is no proper grounding.
and on the topic of sales insurance/warranty - it sounds like someone deliberately did the wrong things on the wiring (ground to neutral) so if there is any recourse on that front, it may help cover the costs.
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Re: Entirely predictable ground loop

Postby Watchmaker » Wed Dec 30, 2020 2:39 am

A couple of thoughts Andy. No advice on how to find a good contractor other than ask your friends. Rating sites like BBB Angie's list are extortion rackets and not worth much imo. Ask peeps you know is best.

As far as the purchase goes...in the purchase and sale agreement, the seller must, by law, disclose all known conditions that may reasonably have a materially negative impact on the sellars intention to buy. This is a question for the attorney present as your representative during close, assuming you had one. These laws vary greatly by state and though I've lived in 8, Florida is not one of them. If memory serves, Florida was founded on a great deal of fraudulent real estate deals after WWI so the law may not be very courteous to buyer's interests. I'd be curious to know.

Equity under a tort claim against the seller for failing to disclose may or may not pan out, but either way, it's not your insurance companies concern. The insurance company only cares about what the terms of your policy state. They might not pay on a claim related to electrical damage if they can prove you knew about faulty wiring though so I strongly encourgae you to not take half measures. I don't envy you, it's a bit of a pickle. Fortunately, it's one that can be solved. good luck man.

edit
+1 for CS70's suggestion to DIY the bits you can. There's no reason why you can't open and close the walls yourself, at least some of it.
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