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t_manero
BX Wire Grounding for Dishwasher

I installed a dishwasher (Bosch brand) that is hard wired to an armored cable (BX ?? - 12 ga. wire) that is from 1964. The armored cable doesn't have a ground wire, but outlet boxes throughout the house are 3-prong (which were sample checked via a circut tester) so this tells me the system is grounded.
The BX cable is attached to the dishwasher using a standard romex box strain relief clamp.
Is this safe ? Does the armored cable serve as the ground to the washer chassis ?.
I noticed a thin wire (18-20 ga.) and appears to be aluminimum that runs in the cable.

canuk
Re: BX Wire Grounding for Dishwasher
t_manero wrote:

I installed a dishwasher (Bosch brand) that is hard wired to an armored cable (BX ?? - 12 ga. wire) that is from 1964.
Providing the 12 ga conductors are copper they can directly connected to the dishwasher terminals. Otherwise, if they are aluminum they need special connectors to transition over to copper for terminating.

The armored cable doesn't have a ground wire, but outlet boxes throughout the house are 3-prong (which were sample checked via a circut tester) so this tells me the system is grounded.
That really depends on if they are properly grounded with the appropriate grounding conductors and terminations.
There's a good chance that 1964 wiring will have grounding conductors in the cables.

The BX cable is attached to the dishwasher using a standard romex box strain relief clamp.
Is this safe ?
Technically no!
There are specific armour cable clamps that are to be used. These are designed with the compatiable metal and clamping mechanisim to ensure a tight positve contact maintaining the grounding path.
Whereas NM strains aren't designed to tightly clamp but rather provide a resistance to pull out.

Does the armored cable serve as the ground to the washer chassis ?.
I noticed a thin wire (18-20 ga.) and appears to be aluminimum that runs in the cable.
In this case yes.

Armour cable ( Type AC ) will have an armor of flexible metal tape and shall have an internal bonding strip of copper or aluminum in intimate contact with the armour for its entire length.
[COLOR=blue]It reduces the inductive reactance of the spiral armour and increases the armour's effectiveness as an equipment ground. The required internal bonding strip can be simply cut off at the termination of the armoured cable, or it can be bent back on the armour. It is not necessary to connect it to an equipment grounding terminal when attached to a metal box. [/COLOR]

The armour of Type AC cable with an internal bonding strip is recognized as an equipment grounding conductor. Older armour cable that does not have the bonding strip can not use the armour as the equipment grounding conductor.

*** Side note ---
BX is a brand name --- orginally registered by GE -- and is commonly used to identify armour cable.
Much like Romex --- which is a brand name -- is used to identify NM cable.

Hopefully this helps.:)

t_manero
Re: BX Wire Grounding for Dishwasher

Thanks Canuk . .. it looks like the AC has an au grounding conductor. I also have a round clamp/strain relief. The screw tightener didn't seem to secure the AC to the clamp so I went with the NM type clamp.
I'll go back to AC clamp/strain relief.

canuk
Re: BX Wire Grounding for Dishwasher

You're welcome. :)

jled96
Re: BX Wire Grounding for Dishwasher

Also make sure you cable jacket is seperated from your conductors with an anti-short bushing, this way if your dishwasher vibrates a lot it will not rub through your wiring, Good Luck!

Re: BX Wire Grounding for Dishwasher
jled96 wrote:

Also make sure you cable jacket is seperated from your conductors with an anti-short bushing, this way if your dishwasher vibrates a lot it will not rub through your wiring, Good Luck!

Good call!

Good Luck from Columbiana, Alabama
Maurice Turgeon,http://thesemi-retiredelectrician.com

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