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All UK companies are required to perform yearly tests of all portable appliances used in the office, redundantly called "PAT tests". I've recently received my first test result sheet, and while all the equipment passed, there are a couple of columns which puzzled me as to what they might mean. Search engine perusal did not turn up anything relevant.

Here are the column headings and values for some of my appliances:

Item    INSRIS      Earth Bond  VIS     Overall

1       >299        0.03        PASS    PASS
2       DI          DI          PASS    PASS
3       L VOLTAGE   L VOLTAGE   PASS    PASS
4       >299        0.1         PASS    PASS
5       DI          DI          PASS    PASS

I think "VIS" might stand for visual inspection, but I'm lost as to what "INSRIS" and "DI" stand for, and what the values in those columns mean. Any thoughts?

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4 Answers

up vote 4 down vote accepted

INSRIS will be insulation resistance. Approximately 500VDS is applied between L/N and E and the current measured. For Class I (earthed) appliances, this should be greater than 1MOhm, though anything below about 5MOhm should be looked into. A lot of appliances will get values in the range of hundreds of MOhm, and I think the tester used in your printout must not read higher than 299MOhm.

VIS is visual inspection.

DI is double insulated, i.e. class II - no earth bond or insulation resistance test to carry out.

L VOLTAGE is low voltage i.e. class III - no earth bond or insulation resistance test to carry out.

I'm not familiar with the specific software or tester used for this printout, but most of the testers will log data and this can be then put into a report.

As stated in another answer, a lot of PAT testing companies just say 12 months between combined inspection and testing. In an office environment (warning PDF), stationary equipment can go 4 years without testing, but hand-held equipment needs testing every year. Visual inspections need to be carried out more frequently. It gets complex when you have a lot of things that need testing and bring new devices onsite.

It is really important to note that these are only guidelines though. As far as I know, there is no law requiring PAT testing, just that you maintain safe electrical equipment.

In a small company I used to work fosense sent two people on a 1 day training course at about £120 each. This paid for itself in a year.

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INSRIS as Mumbles says is Insulation Resistance (INSRES?) and DI is 'Double Insulated'.

Since double insulated appliances have no earth connection, the insualtion resistance and Earth Bond tests do not apply.

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INSRIS:

They can't spell :-)
Insulation Resistance.
Measured in MegOhms.
See guide below.

Earth bond:

Resistance to ground measured at twice fuse rated current.
Typically 0.1 Ohm or 0.5 Ohm if fused jndr 3 Amp.
See guide below.

L Voltage means appliance is operated on LEV so is not required to pass tests. (Typically < 32 CAV or 50 V DC but varies with administration).

DI means Double Insulated. (Corrected from prior guess)


I've hacked apart page 3 from here - a 1993 fact sheet, as a guide.

enter image description here

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INSRIS, would stand for insulation resistance, although I am unsure of what DI would stand for.

You may be able to save your company a fair amount of money as portable appliance testing for office equipment only needs to be done every 48 months, not 12 like many testing companies claim, although IANAL. It is worth reading the guidance given by the hse.

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