Copy app/design/frontend/base/default/template/checkout/onepage/billing.phtml and/or app/design/frontend/base/default/template/checkout/onepage/shipping.phtml to your template folder
add the check on the total value (subtotal, grand total,..) in the class attribute and change YOUR_TOTAL_AMOUNT to the total amount which you need as limit:
Best Answer
If you navigate to:
You'll then have to set up your tax classes/tax rules/customer groups and then in the above section you can assign the correct values to the groups.
http://docs.magento.com/m2/ce/user_guide/tax/vat-validation-configure.html