Is the grounding wire necessary?

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#1: Post by Chert »

I picked up an Olympia Maximatic that had been refurbished and sold by Salvatore and then purchased by the person who lightly used it and sold to me. Shipping or my own moving it about disconnected the motor lead so I took off the surround. Inspecting the motor leads, I noticed that no ground wire connector from motor or solenoid ground was in the machine. I fashioned one and grounded both to the frame. The ground lead from boiler plate to frame was in place.

Is there harm in omiting the ground wire from solenoid and motor?
The Maximatic has no auto fill or dosimeter so there is no circuit board in the machine.

I think the person who let it go from Salvatore sans grounding did not feel it worth the trouble to connect grounding wires. Much work on that machine without disassembly is fiddly because of the size of things. It took me an hour to free up the little nut and then replace it with the new ground lead attached to frame. While I was in there I also added boiler insulation.

The machine is working nicely now, BTW.
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#2: Post by BaristaBoy E61 »

Sounds like you're OK to me with the ground wire connected to the frame. If you own a digital volt/ohm meter, you can verify the grounding of the parts you mentioned by unplugging the machine and test to see if there is very low resistance between the frame and whatever parts you would like to test, such as the boiler(s), solenoid, pump, etc.

Anything that is directly screwed or bolted to the frame should be grounded.

'Should' be OK without a ground; better with a proper ground. I would at least leave the ground wire you attached to the frame.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"


#3: Post by bettysnephew »

Obviously from a safety standpoint grounded would be best. As an aside, years ago I had a Maytag clothes dryer with the moisture sensing bars in the tub. It began to leaving clothing damp at the end of the cycles. The problem ultimately turned out to be a broken earth wire on the back of the machine (the electrical outlet was properly grounded) which was upsetting the electronic sensor bar signal. I have also experienced issues with many electronic devices in my maintenance career that were directly related to poor earth grounds. With our machines becoming more reliant on electronic controls, grounding becomes more important to proper function.
Suffering from EAS (Espresso Acquisition Syndrome)
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#4: Post by AssafL »

I don't know what the code requirements are now, but I think that as long as one of the screws connecting the motor to the frame has a spring washer (the kind that pierces oxidation and thus cold welds to the grounded frame) you should be fine.
Scraping away (slowly) at the tyranny of biases and dogma.

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Chert (original poster)
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#5: Post by Chert (original poster) »

I know I grounded the components adequately.

But that is not the question. Why would a reputable machine maker refurb a machine and leave those components un-grounded? Is the grounding to those components necessary? Is the lack of it such low risk as to: why bother? Is the grounding wire necessary?
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#6: Post by civ »

Chert wrote:Is the grounding wire necessary?

If whoever tinkered with the unit at one time or another left some ground point unconnected, connect it back.

Anything that has a metal surface and is connected to live should be grounded.
ie: the motor casing to the chassis and the chassis to ground via the appropiate ground cable/point.
Should for whatever reason the contact point between the motor casing and the chasis (where it is bolted on) fail, you would otherwise be without a proper ground.

In the case I am mentioning, to depend on the motor casing to be grounded by itself because it is bolted to a part of the chasis is poor practise.

Just my 0.02 and what I was taught at school.
As always, YMMV.




#7: Post by SJM »

So, still no one is answering the question as to why Salvatore would have chosen to do something which is apparently so unacceptable.
Wouldn't someone buying something from Salvatore expect better ?

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#8: Post by civ »

SJM wrote: ... why Salvatore would have chosen to ...
We don't know if this is really so.

For all we know, the machine could have left the OEM without the grounding cables in place.
I have seen this happen in other electrical equipment/appliances.

I have also seen different manufacturing runs where a couple of years after the first one, safety measures considered redundant were dropped.
A case in mind is my ca. 2000 Cimbali Junior Max which has more over-temperature protections than what is shown in the electrical circuit they sent me at my request a few years later.

Also, could it not have happened at some point after it left Salvatore's workshop?

To assume that it was Salvatore's choice is, to put it mildly, a bit extreme.


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#9: Post by baldheadracing »

What is the age of the machine? I wouldn't expect today's electrical standards on a machine from yesteryear. My MCaL from 1985, my Silvia from 2006, and Simonelli MDX grinder and Program 2-group from the '90's all rely only on the chassis to ground components. The MCaL doesn't even have a temperature overlimit on the boiler!
What I'm interested in is my worst espresso being fantastic - James Hoffmann


#10: Post by stanp »

my similar caffarex came new without ground connections.
picture of a caffarex in this article:
Olympia Caffarex
it is common for one end of the coil to be grounded to the mounting base.